Behavior Analysis of Concrete and Steel Structure with...

Journal of Science and Technology – Institut Teknologi Sumatera

Behavior Analysis of Concrete and Steel Structure with Levelling Time

History Method (Case Study of Gedung E ITERA)

Rijuli Nadeak1, Ahmad Yudi1, Bayzoni2, Nugraha Bintang Wirawan1

1Civil Engineering Department, Institut Teknologi Sumatera, Lampung Selatan, Indonesia

2Civil Engineering Department, Universitas Lampung, Bandar Lampung, Indonesia

Abstract:

The selection of structural material types can be based on analyzing the behavioral of the structure by giving a

nonlinear dynamic earthquake load of time history. Because in Indonesia doesn’t have any data of time history record,

it is necessary to match the time history data with the design spectrum response. Gedung E Itera is modeled on

reinforced concrete structures and steel structures with open frame models for the same as built drawing. Then can be

evaluated the structural behavior that is like mass participation, plastic design, displacement, rotation, and base shear

with time history load that will be levelling (levelling time history). With levelling the time history load , it can be

found the first structural part that collapses and the maximum load that can be retained by the structure for one of the

mitigation effort. The analysis uses a nonlinear dynamic time history analysis with the most dominant combination is

earthquake combination. The results of this study show the differences in structural performance, the location of

structural failure, and the maximum load that can be retained by the reinforced concrete structure and steel structure

of gedung E Itera.

Keywords : Structural performance, time history, reinforced and steel structure.

1. Introduction

The acceleration of development in the field of technology by the central government for the readiness of

human resources in Sumatra is the forerunner to the formation of the Sumatra Institute of Technology

campus. This college is located in the province of Lampung. Student admissions that continue to increase

will certainly require college support facilities, one of the most basic of which is the lecture building. Since

it was inaugurated in 2014, the Institute of Technology in Sumatra has had several main buildings used

both for lecture halls and campus administration rooms. One of the newly inaugurated buildings in 2017 is

ITERA Gedung e which is a building grant from the government of Bandar Lampung to the Sumatra

Institute of Technology to support the running of lectures.

At present the building structure that is often applied to buildings is monolithic concrete structures, precast

concrete structures and steel structures. These three types of structures have their respective advantages in

terms of their application, both in terms of economics and in terms of structural behavior. In Sumatera

Institute of Technology, the building structure applied is a type of reinforced concrete. The use of reinforced

concrete in this lecture building raises the question why the applied structure is reinforced concrete, while

the existing technology has enabled the use of precast concrete or steel structures.

One of the lecture buildings at ITERA whose capacity is quite large is the E ITERA building. The four-

story building and has a basement also uses reinforced concrete. Many factors can be used as parameters to

assess the most optimum type of building structure. One of the most commonly used factors is the economic

factors related to the efficiency of the material to be used. In addition, serviceability factors also play an

important role because with various loads that the structure will receive, it must be ensured that the structure

of the building remains safe.


In this study the author wants to compare two types of structures with existing architectural designs. The

building used for this case study is one of the lecture buildings in ITERA namely the E ITERA building.

The type of structure to be compared is the concrete structure and steel structure. The review that will be

done to compare a better structure is by reviewing the structural behavior of the type of structure applied.

One way to get results from structural behavior is to give styles to the structure. One style with a high level

of abstraction is an earthquake style that is very irregular and its duration is also very random. This

simplification of earthquake force can be in the form of spectrum response and time history analysis. In this

study the seismic load used is a time history load that has been patched in response to the spectrum of

Lampung region. The time history earthquake load is increased by its Aog (initial earthquake acceleration)

gradually until obtaining all the structures has failed in order to see the structure behavior gradually. The

same loading method will be used in each concrete structure and steel structure for the case study of the E

ITERA building.

2 . Literature Review

2.1. General review

2.1.1. Reinforced Concrete Structure

Concrete is a mixture of portland cement or other hydraulic cement, coarse aggregates, fine aggregates, and

water, with or without additional mixtures forming solid masses (SK SNI T-15-1991-03). This mixture will

form an artificial stone whose strength varies depending on the planned mixture.

Reinforced concrete itself is a combination of two materials, namely: concrete and steel (reinforcement)

which in its planning must refer to the standards in Indonesia SNI 2847-2013 concerning the requirements

of structural concrete for buildings. The advantages of concrete material are strong compressive resistance,

while steel (reinforcement) is a very good material to resist tensile and shear. The combination of these two

materials is expected to be able to withstand tensile forces, compressive forces and shear forces so that a

building structure remains strong and safe. The use of reinforced concrete in building structures includes:

foundations, beams, columns, plates, shearwall walls.

2.1.2. Steel Structure Steel is a metal alloy between iron (Fe) and carbon (C), where iron as a basic element and carbon as its

main alloying element. The carbon content in steel ranges from 0.2% -7.7% by weight according to the

grade. In the steel making process there will be other elements besides carbon that will be left in steel such

as manganese (Mn), silicon (Si), cromium (Cr), vanadium (V) and other elements (Bolton, 1998). The use

of steel materials in the building structure has also spread widely to various sectors, even construction using

steel structures will seem more modern compared to reinforced concrete structures. Steel structure buildings

have a main steel frame structure, namely columns, beams, floors and roofs.

Planning the structure of steel buildings in Indonesia refers to SNI 1729-2015 regarding specifications for

structural steel buildings. The advantage of steel material is that it has a very high tensile strength. Besides,

steel is also more flexible and lighter when compared to concrete in its use.

2.1.3. General Concept Ductility is the ability of a building structure to experience large post elastic displacements repeatedly and

back and forth due to earthquake load above the earthquake load which causes the first melting while

maintaining sufficient strength and stiffness so that the building structure remains standing even though it

is in on the verge of collapse (Budiono and Supriatna, 2011: 17). Deformed structures can mean elongated,

shortened, and bent. The ductility factor of a building structure is the basis for determining the seismic load


that works on the building structure, therefore achieving the level expected to be well guaranteed. This can

be achieved if the beam has to melt before the damage occurs in the column (the concept of strong column

weak beam). This means that due to the influence of the earthquake plan, plastic joints in the building

structure are only at the ends of the beam and on the foot of the column.

In a more detailed sense ductility is the ability of a structure to experience large post elastic displacements

repeatedly and back and forth due to an earthquake load which causes the first melting, while maintaining

sufficient strength and stiffness, so that the structure remains standing even when it is at condition of the

threshold of collapse. In planning earthquake resistant buildings, the formation of plastic joints that are

expected to occur in the structure when a large earthquake occurs needs to be controlled and its location is

limited to the structural components. In the frame structure it would be better if the dissipation of earthquake

energy through melting (plastic joints) on the beam and column components are expected to provide

strength, stiffness and stability when holding forces acting through bending, shearing and axial action. The

space frame system inside the structural components and their joints withstand forces acting through

flexural, shear and axial action is called the Moment Resisting Frame System.

2.2. Structure Dynamics Structural dynamics is one part of mechanics that specifically discusses structural responses to dynamic

loads, for example due to earthquakes. In the discussion of structural dynamics, the load and response

structure is not only determined by the direction, location, and magnitude, but also by the time variable. In

particular, the magnitude of the structural response in the form of internal forces is a function of time, as a

form of response to disturbances or external loads, whose formula is determined by the parameters of the

structure in question, the mass, stiffness and attenuation affecting the vibration experienced by the structure.

2.2.1. Degree of Freedom (Degree of Freedom) According to Widodo (2001) the degree of freedom is the degree of independence needed to state the

position of a system at any time. If a point is observed experiencing a horizontal, vertical and sideways

displacement, for example, the system has 3 degrees of freedom.

According to Mario Paz (1996), in general a continuous structure has an infinite number of degrees of

freedom. But with the process of idealization or selection, an appropriate mathematical model can reduce

the number of degrees of freedom into a discrete number and for some circumstances can become a single

degree of freedom.

2.2.2. Degree of Single Freedom (Single Degree of Freedom) A mass system that moves in one direction, namely the horizontal direction, is called a single degree of

freedom (SDOF) system. In SDOF systems, the structure is modeled with a single mass and a single

displacement coordinate. The elements that influence this system are mass, structural stiffness, attenuation,

and external force. The following in Figure 1 is an example of a mathematical model of SDOF.

Figure 1 Mathematical Model of SDOF

Source: Dynamics of Theory & Calculation Structure, Mario PAZ (1996)


2.2.3. Many Degrees of Freedom (Multi Degree of Freedom) Mathematical models that represent a system of multiple degrees of freedom (MDOF) can be seen in Figure

2.

Figure 2 Mathematical Model of MDOF

Source: Dynamics of Theory & Calculation Structure, Mario PAZ (1996)

A structure has a natural frequency as much as the degree of freedom it has and if the dynamic load received

by the structure has a frequency close to the natural frequency of the structure, there will be a resonance

which will result in collapse or collapse of the structure.

2.3. Irregular and Irregular Building Structure According to SNI 1726-2012 article 7 structure of buildings must be classified as regular building structures

and irregular building structures. For regular building structures procedures can be used equivalent static

analysis and for irregular building structures, seismic effects of the plan must be reviewed as the effect of

dynamic loading. The analysis that can be used for irregular building structures is spectrum response

variance analysis and dynamic response analysis of linear and nonlinear time histories. In this research is

used irregular building structure planning with the analysis used is a time history dynamic response analysis.

3 . Research Methodology

3.1. Flow diagram The sequence of this research implementation process can be seen in the following flow chart:


Figure 3 Flow Chart


Figure 4 Earthquake Load Flow Chart

3.2. Identification of problems In this study problem identification is the first step in determining the importance of this research. And at

this stage the problem that arises is the territory of Indonesia which is located in an area that often happens


earthquakes. The earthquake that will occur will be a burden that will be received by a structure and must

be ensured the structure of the building where there is an earthquake around it must remain safe. The

structures commonly used in building construction are concrete structures, precast concrete structures and

steel structures which in this case the E ITERA building has been constructed using reinforced concrete

structures. Do not rule out the possibility that other buildings to be built at the Sumatra Institute of

Technology will use other materials such as steel structures. Because one that must be taken into account

in planning a structure is the earthquake load that will be received by the structure, then by giving different

earthquake loads it can be seen the performance of a structure.

3.3. Data collection This study requires supporting data to be used. These data are in the form of E ITERA (existing) building

structure data. In addition earthquake data is also needed in this study which is earthquake data design

response spectrum and earthquake data Loma Prieta AGM02. After the data has been collected, the data

compilation process will be carried out which will then be modeled on SAP2000.

3.4. Structure Modeling In this study structural modeling uses structural analysis software, SAP2000 version 14. The as built

drawing of the gedung E ITERA is modeled using two structural systems, namely: reinforced concrete

structures and steel structures. Modeling is made in the form of open frames with column and beam

structures. The dimensions of the modeling of the concrete structure are obtained from the as built drawing

gedung e. While for the modeling of the steel structure is obtained from trial and error.

3.5. Parameters of Structural Behavior Analysis Analysis of time history dynamic response by using a time history load that will be increased by Ao (initial

earthquake acceleration) several times until the structure reaches collapse in order to see the structure

behavior gradually. The structure behavior that will be reviewed as a parameter to compare the two types

of concrete and steel structures is as follows:

1. Check Mass Participation

The purpose of checking mass participation is to find out the shape mode of the structure that

experiences participation reaching 90% of the three directions of the motion pattern (translational-x,

translational-y, and z-rotation) structure.

2. Check Plastic Design

Once it is known which part of the structure will be used as a reference in checking the plastic design,

Aog (initial earthquake acceleration) will be increased until the structure conditions collapse (collapse).

3. Displacement

Displacement from the top of the structural system which is the output of SAP will be checked together

with the increase in Ao (earthquake acceleration) by comparing the boundary limits in accordance with

the rules on SNI. In the plastic design will also be carried out displacement checking in accordance

with FEMA 356.

4. Rotation

The rotation value will be seen in the SAP output and then compared to the plastic joint condition

boundary which refers to FEMA 356.

5. Check Base Shear Structure

Base shear checking obtained from SAP output will also compare the shear force values in both types

of concrete and steel structures in accordance with the increase in earthquake acceleration.

4 . Results and Discussion

4.1. Structure Description The reinforced concrete structure design is adapted to the as built drawing of gedung e ITERA and the steel

structure design which is the result of trial and error design with the as built drawing of gedung E ITERA.


The structure to be reviewed is concrete and steel structures. The structure is modeled as shown in Figure

5, where the structure is divided into 2 main parts. The first structure that extends the y direction and the

second structure is a smaller structure and is next to the first structure.

Figure 5 3D View of the Concrete Building Structure of the E ITERA Building

4.2. Description of loading

One of the objectives of this study is to evaluate the performance of the behavior of the structure being

reviewed. Therefore, the concrete and steel structures that have been modeled will be given loads to see the

performance of the structure. At the time of modeling the structure of the beam and column is modeled as

open frame so that the load that works will be directly received by the structural elements.

The most dominant combination of loading in this study is earthquake load. The earthquake load that will

be received by the structure is an earthquake load time history that will be modified later. In addition to

earthquake loads, the combination of loading used in the case study of the ITERA E building is a burden

that is regulated in the applicable loading regulations in Indonesia based on SNI 03-1726-2012. And for the

earthquake load that will be used in this structural analysis is the time history that will be adjusted to the

response of the spectrum of the region and the condition of the soil where the structure is located.

4.2.1. Time History

Time history or time history data is obtained from records of earthquake accelerometers when an earthquake

occurs in an area. In this case the Loma Prieta E-W accelerogram (Figure 6) was recorded on October 17,

1989 in the northern part of California.


Figure 6 AGM02 Acceptor (Loma Prieta E-W, October 17, 1989)

This acceleration data will be adjusted in response to the design spectrum for the South Lampung region.

4.2.2. Spectrum Response Analysis of calculation of response spectrum design takes data from Puskim Ministry of Public Works

PUPR website (puskim.pu.go.id) in the form of Ss, S1, Fa, and Fv data which then after calculation in

accordance with SNI-1726-2012 with earthquake source and hazard maps 2017 will produce a spectrum

response curve.

The results of the calculation of the design spectrum response can be seen in Figure 7 that is the spectrum

response curve with abscissa time and ordinate acceleration.

Figure 7 Spectrum Response Curve

-1.5

-1

-0.5

0

0.5

1

1.5

0 20 40 60 80 100 120 140 160

Acc

eler

ati

on

(m/s

2 )

Time (s)

AGM 02

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Per

cep

atan

(Sa

)

Time (s)

Design Spectrum Response


4.2.3. Matching and Leveling Process In SNI 1726-2012 it is stated that ground motion must be scaled in such a way that in the range of 0.2T to

1.5T the average value of acceleration is not less than the ordinate value associated or adjacent to the design

spectrum response. In this study matching earthquake recordings were first multiplied by a number so that

the spectrum response of the accelerogram approached the spectrum response based on SNI for the

Lampung region with soft soil conditions.

Multiplication data which is the acceleration and time data will be drawn using Seismosignal software from

Seismosoft so that the AGM02 recording plot results can be obtained as shown in Figure 8. The output data

from the seismosignal is the acceleration of the time that has been adjusted with the spectrum response of

E building location ITERA is located. Display of comparison between spectrum response curve based on

SNI and time history that has been matched can be seen in Figure 9.

Figure 8 Spectrum Response Image Output from Seismosignal Software

Figure 9 Comparison of Time History and Spectrum Response

In the analysis using SAP2000 earthquake record AGM02 that has been matched with the response

spectrum of Lampung region will be increased Aog (earthquake acceleration) several times and examples

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 1 2 3 4 5

Acc

eler

ati

on

(g

)

Time (s)

Spectrum Response vs AGM02


can be seen in Figure 10. Increased initial earthquake acceleration aims to see the performance (structural

behavior) of concrete and steel gedung e ITERA in every increase in Aog.

Figure 10 Leveling Results of Aog Time History

4.3. Structural Analysis Structural analysis is carried out using the help of SAP2000 application to obtain the results of structural

behavior that will be reviewed in the next section, namely mass participation, check plastic design,

displacement, rotation, and base shear on both types of concrete and steel structures. After modeling on

SAP, structural analysis will be carried out in this study, the structural analysis stage is carried out in

accordance with the initial acceleration of earthquake time history that has been matched with the design

spectrum response. The analysis used is time history nonlinear dynamic analysis.

4.3.1. Check Mass Participation Checking the participation of the masses was carried out to find out about the mode conditions (vibrational

variance) where some structures experienced mass participation reaching 90% (in accordance with SNI

1726-2012). Where the mode is used as a reference for determining the dominant motion pattern. The

results of the vibration range for the concrete structure are listed in Table 1 and the steel structure in Table

2.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Acc

eler

ati

on

(g)

Time (s)

Levelling AOG Time History

1 AOG

1.5 AOG

2 AOG


Table 1 Participation of Concrete Structure Mass

From the data above it can be seen that the concrete structure mode achieves 90% mass participation in 3

motion patterns. In the translational-x motion pattern which has reached 90% is in mode 17. In the direction

of translational-y motion pattern mass participation reaches 90% occurs in mode 18. And the rotazi-z

motion pattern reaches 90% in mode 16.

Table 2 Mass Participation of Steel Structures

ix UX Shape iy UY Shape iz UZ Shape

1 0.935855 51.0620 51.062 0.042 0.042 67.209 67.209

2 0.875618 0.1990 51.261 17.046 17.089 5.18 72.389

3 0.771157 0.0800 51.341 0.344 17.432 1.119 73.508

4 0.754685 0.0009 51.342 33.462 50.894 1.515 75.023

5 0.676395 0.0051 51.347 24.614 75.509 0.16 75.183

6 0.63096 26.1480 77.495 0.00098 75.51 3.623 78.806

7 0.614702 0.1110 77.606 0.157 75.667 1.731 80.537

8 0.58907 1.5840 79.19 0.025 75.692 1.648 82.185

9 0.561302 0.0820 79.272 0.021 75.713 0.031 82.216

10 0.507839 1.5660 80.839 0.001 75.714 0.328 82.544

11 0.448267 2.0180 82.857 0.011 75.725 2.201 84.745

12 0.438511 0.0150 82.872 1.828 77.554 0.716 85.461

13 0.364047 0.6500 83.522 1.559 79.112 0.091 85.552

14 0.357696 3.2970 86.819 0.377 79.49 1.849 87.401

15 0.30916 2.7480 89.568 0.016 79.506 2.334 89.735 Rotation-Z

16 0.255101 0.0089 89.576 Translation-X 6.441 85.947 0.41 90.145 Rotation-Z

17 0.206031 4.7060 94.283 Translation-X 0.156 86.103 Translation-Y 2.059 92.204

18 0.193337 0.1020 94.384 6.055 92.158 Translation-Y 0.448 92.652

Mass Participation (%)Moode

T

(second)

ix UX Shape iy UY Shape iz UZ Shape

1 0.909629 0.0001 0.0001 21.256 21.256 7.064 7.064

2 0.834771 0.0010 0.00113 0.326 21.583 0.095 7.159

3 0.763924 44.4800 44.481 1.1E-05 21.583 56.661 63.819

4 0.739606 0.0110 44.492 0.846 22.428 0.514 64.333

5 0.73026 0.1830 44.675 0.588 23.016 0.76 65.093

6 0.720494 0.4830 45.157 0.105 23.121 0.833 65.926

7 0.66782 0.8460 46.003 0.014 23.134 0.558 66.484

8 0.645447 0.0000 46.003 1.889 25.023 0.027 66.511

9 0.635688 1.6380 47.641 0.357 25.38 3.385 69.896

10 0.626294 0.0180 47.659 43.693 69.073 0.525 70.421

11 0.594697 0.1270 47.786 0.00123 69.074 0.064 70.485

12 0.548158 0.0300 47.816 4.915 73.989 0.185 70.671

13 0.524527 8.7530 56.569 0.924 74.913 0.788 71.459

14 0.52174 3.7360 60.306 2.01 76.923 1.398 72.856

15 0.482105 0.3070 60.612 0.391 77.314 0.05 72.907

16 0.468769 15.1840 75.796 0.00302 77.317 3.598 76.505

17 0.394312 0.5400 76.336 0.00205 77.319 0.075 76.58

18 0.324738 0.2590 76.595 0.275 77.594 0.647 77.227

19 0.31492 3.522 80.117 0.026 77.62 3.423 80.651

20 0.252419 4.551 84.668 0.047 77.667 2.187 82.838

21 0.241362 0.029 84.696 Translation-X 7.802 85.469 0.334 83.172

22 0.166368 6.328 91.024 Translation-X 0.289 85.758 Translation-Y 5.738 88.91

23 0.161942 0.355 91.379 5.341 91.099 Translation-Y 0.07 88.979

24 0.099331 0.351 91.731 3.819 94.917 0.548 89.528 Rotation-Z

25 0.096404 4.422 96.153 0.262 95.179 0.941 90.469 Rotation-Z

Mass Participation (%)Moode

T

(second)


In the steel structure mode which has reached 90% mass participation in the direction of 3 motion patterns

occurs in different modes. In the translational-x motion pattern that has reached 90% is in mode 22. In the

direction of translational-y motion pattern, mass participation reaches 90% in mode 23. And in the motion

pattern of rotazi-z mass participation reaches 90% occurs in mode 25.

4.3.2. Plastic Design Check Checking the plastic design is done by increasing Aog (0.234g) to reach the conditions above CP (Collapse

Prevention). Before reaching the collapsing condition, the plastic joint will pass through several stages of

constraints as in the curve in Figure 11. By using SAP2000, the output of these boundaries will be seen in

the form of a color indicator as will be explained next.

Figure 11 Plastic Joints

B: elastic boundary, the first plastic joint is formed in pink.

IO: immediate occupancy, plastic joints are formed in dark blue.

LS: life safety, plastic joints are formed in light blue.

CP: collapse prevention, plastic joints are formed in green.

Plastic joints are formed at the ends of members, be they beams or columns. The process of forming plastic

joints together with the increased earthquake load received by concrete and steel structures (in this case the

earthquake time history). The earthquake load received by the member structure will cause each member

to increase the rotation value and moment. When a member of a structure has experienced a rotation value

and a certain moment, the plastic joint will form.

In reinforced concrete structures, gedung e ITERA, the condition when plastic joints formed had already

exceeded collapse prevention (CP) began to be achieved when the structure received an earthquake with an

initial acceleration of 2 times the initial acceleration of the earthquake (0.468g) as in Figure 12. And the

steel structure conditions when Plastic joints have reached the conditions above CP when the steel structure

receives earthquake loads with an initial acceleration of 3.4 times the initial earthquake acceleration

(0.7956g) as shown in Figure 13.


Figure 12 Plastic Joint Indicators 2 x Aog Concrete Structure

When the concrete structure has not received an earthquake load, the plastic joint is still not formed, and

when given an earthquake load with the initial earthquake acceleration, the plastic joint indicator that is

formed is almost all in purple (elastic boundary) and concrete structure with 208 members (circled in color

black in Figure 12) is the member who first reaches the immediate occupancy condition (blue in the

indicator). The same thing happens when the earthquake load is increased by the initial acceleration of the

earthquake, the plastic joint indicator changes occur gradually and those who always reach the plastic

boundary conditions are the 208 members.

The member used as a reference in plastic design checking is member number 208 (marked in Figure 12)

because the first member experienced a collapse which is marked by changes in the plastic joint color

indicator. Plastic joint indicators will appear on both ends of the member. The member is a y direction beam

with a cross section size of 250x500 mm (bxh) in the model of the concrete structure of the E ITERA

building.

Figure 13 Plastic Joint Indicators 3.4 x Steel Structure Aog

In the initial stage when the steel structure receives an earthquake load with an initial earthquake

acceleration (0.234g) almost all the plastic joints formed show an elastic boundary condition, but one

member has reached the immediate occupancy condition (blue on the indicator) ie 130 members (circled in

color black in Figure 13). The same thing happens when the earthquake load is increased by the initial


acceleration of the earthquake, the plastic joint indicator changes occur gradually and those who always

reach the boundary conditions at the plastic joint are first 130 members.

The member steel structure that is used as a reference in plastic design checking is member number 130

(shown in Figure 13) because the member who first experienced a collapse in SAP is marked by a change

in the indicator color of the plastic joint. Plastic joint indicators will appear on both ends of the member.

The member is a beam with a cross section of 300x150 mm IWF profile on the steel structure model of the

E ITERA building.

Plastic joints are formed when a condition has been reached. In this case the SAP2000 plastic joint

application is formed and can change according to the color of the indicator in the image often with an

increase in the rotation value and moment in the structure.

4.3.3. Displacement Checking the horizontal direction displacement from the top of the structural system is seen from the SAP

output compared to the displacement limits set out in SNI 1726-2012 and FEMA 356.

Based on SNI 1726-2012 interstory displacement of 1.5% from the level below the level reviewed. In the

concrete structure of the ITERA E building there are 2 joint points taken as a point of review of the

intersection as seen in Figure 14, namely joint 1128 (J1128) and joint 709 (J709). Whereas the steel

structure of E ITERA building was carried out in two different joint points, namely joint 1128 (J1128) and

joint 709 (J709) as shown in Figure 15 against the allowable displacement limits.

Figure 14 Concrete Joint Structures Reviewed


Figure 15 Joint Steel Structure Reviewed

The concrete displacement between the floors on the joint is also checked along with the increase in aog as

shown in Table 3. While the displacement data on the two steel structure joints can be seen in Table 4.

Table 3 Concrete Structure Displacement (SNI 1726-2012)

PGA (g) Displacement, S (m)

S limit (m) J1128 J709

0.234 0.060381 0.018507 0.045

0.351 0.089083 0.028693 0.045

0.3744 0.094937 0.030719 0.045

0.3978 0.100812 0.032754 0.045

0.4212 0.106752 0.034807 0.045

0.4446 0.112583 0.036816 0.045

0.468 0.118506 0.038874 0.045

Table 4 Displacement of Steel Structures (SNI 1726-2012)

PGA (g) Displacement, S (m)

S limit (m) J1128 J709

0.234 0.093193 0.013603 0.045

0.351 0.135845 0.020395 0.045

0.468 0.175601 0.027147 0.045

0.585 0.213911 0.033686 0.045

0.702 0.252024 0.040152 0.045

0.7488 0.267661 0.042669 0.045

0.7722 0.27552 0.043884 0.045

0.7956 0.283378 0.045125 0.045

From the data in Table 3, it can be seen that the concrete structure of the ITERA E building has passed the

permit displacement value (SNI 1726-2012) in the acceleration case of 0.234g at joint 1128 but has not

passed the displacement permit on joint 709. The same thing happened when an earthquake acceleration

was increased (as shown in Table 3).


Whereas from the data in Table 4, it can be seen that the steel structure of ITERA E building has passed the

value of permit displacement (SNI 1726-2012) in the case of acceleration of 0.234g earthquake at joint

1128 but has not passed the displacement permit on joint 709. When an earthquake load acceleration up to

3 , 3 times the initial acceleration of the earthquake (0.7722g) joint 709 is still at the permit displacement

limit. It was only at the acceleration of the earthquake load that it had been increased to 3.4 times (0.7956g)

2 joints which were reviewed through the permit displacement.

By using the standard in FEMA 356 with the limitations of 1% immediate occupancy, LS (life safety) 2%,

and CP prevention (collapse prevention) of 4% of the level below the level reviewed, the FEMA 356

displacement data on the concrete structure can be seen in Table 5. And by using the standard in FEMA

356 with the conditions of immediate occupancy 0.7%, LS (life safety) 2.5%, and CP (collapse prevention)

of 5% of the level below the level reviewed then Displacement data based on FEMA 356 on the steel

structure can be seen in Table 6.

Table 5 Concrete Structure Displacement (FEMA 356)

PGA (g) Displacement, S (m) IO = 1%

(m) LS = 2%

(m) CP = 4%

(m) J1128 J709

0.234 0.060381 0.018507 0.03 0.06 0.12

0.351 0.089083 0.028693 0.03 0.06 0.12

0.3744 0.094937 0.030719 0.03 0.06 0.12

0.3978 0.100812 0.032754 0.03 0.06 0.12

0.4212 0.106752 0.034807 0.03 0.06 0.12

0.4446 0.112583 0.036816 0.03 0.06 0.12

0.468 0.118506 0.038874 0.03 0.06 0.12

Table 6 Steel Structure Displacement (FEMA 356)

PGA (g) Displacement, S

(m) IO = 0.7%

(m) LS = 2.5%

(m) CP = 5%

(m) J1128 J709

0.234 0.093193 0.013603 0.021 0.075 0.15

0.351 0.135845 0.020395 0.021 0.075 0.15

0.468 0.175601 0.027147 0.021 0.075 0.15

0.585 0.213911 0.033686 0.021 0.075 0.15

0.702 0.252024 0.040152 0.021 0.075 0.15

0.7488 0.267661 0.042669 0.021 0.075 0.15

0.7722 0.27552 0.043884 0.021 0.075 0.15

0.7956 0.283378 0.045125 0.021 0.075 0.15

From Table 5 it can be seen using the FEMA 356 standard, the concrete structure of the E ITERA building

has reached life safety conditions in the 0.234g earthquake for joint 1128. And for the joint 709 it is still in

the immediate occupancy condition at 0.234g earthquake. The same thing happened in the two joints which

was reviewed when an earthquake acceleration was increased (as shown in Table 5).

It can be seen that both using the SNI standard, increasing the earthquake up to 2 times the initial earthquake

did not deliver the entire structure through the permit displacement. And using FEMA356 the concrete


structure of the E ITERA building had not yet reached a collapse prevention condition when an earthquake

acceleration was increased to 0.468g (2 times the initial earthquake acceleration).

Whereas in steel, from Table 6 can be seen using the FEMA 356 standard, at the initial earthquake

acceleration (0.234g) the joint 709 condition is still in the immediate occupancy condition and joint 1128

is already in a life safety condition. And then at 0.468g earthquake load acceleration the displacement

reached collapse prevention condition on joint 1128.

Thus the checking of steel structure displacement using SNI 1726-2012 or using FEMA356 standard states

that for steel structures only shows one of the two dominant joint reviews that have exceeded the permit

intersection limit of joint 1128.

4.3.4. Rotation The structural rotation check is seen from the SAP2000 output which is then compared to the boundary

conditions for each concrete and steel structure. Rotation checking is carried out every increase in Aog

(initial earthquake acceleration) from initial earthquake conditions (original) until the rotation of the

structure reaches a collapsing condition.

For the condition of rotation value on the concrete structure of the E ITERA building can be seen its

representation in Table 7. And the member used to review the value of rotation on the structure is member

number 208 according to the member which is used as a reference for checking the plastic design of E

ITERA building concrete structures.

And for the steel structure of the E ITERA building the conditions of the rotational values reviewed are

represented in Table 8. The members used to review the rotation value of the steel structure are number 130

members according to the member used as a reference for plastic design checks on the steel structure of the

E ITERA building.

Table 7 Rotation of Concrete Structures

Table 8 Rotation of Steel Structures

(+) (-) (+) (-) (+) (-)

0.234 0.01243 -0.01243 0.01459 -0.01459 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.351 0.01907 -0.01907 0.02259 -0.02259 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.3744 0.02041 -0.02041 0.0242 -0.0242 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.3978 0.02174 -0.02174 0.02581 -0.02581 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.4212 0.02307 -0.02307 0.02743 -0.02743 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.4446 0.02441 -0.02441 0.02901 -0.02901 0.01 -0.01 0.02 -0.02 0.025 -0.025

0.468 0.0257 -0.0257 0.03059 -0.03059 0.01 -0.01 0.02 -0.02 0.025 -0.025

CPθmax

(rad)

θmin

(rad)

θmax

(rad)

θmin

(rad)

PGA (g)

0.05 0.95IO LS

(+) (-) (+) (-) (+) (-)

0.234 0.01248 -0.01248 0.01312 -0.01312 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.351 0.01987 -0.01987 0.02045 -0.02045 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.468 0.02788 -0.02788 0.0285 -0.0285 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.585 0.03592 -0.03592 0.03662 -0.03662 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.702 0.04408 -0.04408 0.04477 -0.04477 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.7488 0.04738 -0.04738 0.04807 -0.04807 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.7722 0.04904 -0.04904 0.04972 -0.04972 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

0.7956 0.0507 -0.0507 0.05138 -0.05138 0.00175 -0.0018 0.014 -0.014 0.021 -0.021

PGA (g)

0.05 0.95IO LS CP

θmax

(rad)θmin (rad)

θmax

(rad)θmin (rad)


The increase in the initial earthquake acceleration in the concrete structure was carried out up to 0.468g (2

x Aog) because the plastic joint indicator had exceeded CP at the SAP output (the indicator was orange).

From Table 7 it can be seen that in the earthquake 0.3978g the condition of CP (collapse prevention) had

begun to form and in the 0.468g earthquake (2 x Aog) the CP condition had been reached. This condition

can occur because the rotation value at the edges of the frame has exceeded the rotation value limit in

FEMA 356 (according to the standard used in SAP).

Whereas in the steel structure the increase in earthquake acceleration was carried out from one time of

earthquake acceleration (0.234g) to 3.4 x earthquake acceleration (0.7956g). At 0.7956g earthquake

acceleration the indicator condition of plastic joints on SAP has reached yellow color (above CP). From the

data above it can be seen that at the initial earthquake acceleration (0.234g) the entire structure is still in an

immediate occupancy, but in the earthquake condition 0.468 (2 x initial earthquake) the collapse prevention

condition was reached. Likewise, when the earthquake condition was increased to 3.4 times the initial

earthquake acceleration, it was in collapse prevention. This can be known based on the limitation conditions

of IO, LS, and CP as can be seen in Table 8 above.

4.3.5. Base Shear This base shear is the result of dynamic shear force analysis with the most dominant loading combination

of time history combination.

For reinforced concrete structures, the value of base shear for non-linear dynamic seismic load time history

is shown in Table 9 and for steel structures base shear values for the same earthquake load (TH combination)

are shown in Table 10.

Table 9 Base Shear of Concrete Structure

PGA (g) Nilai Base Shear (kN)

0.234 43935.725

0.351 65555.331

0.468 87152.566

Table 10 Base Shear of Steel Structure

PGA (g) Nilai Base Shear (kN)

0.234 16419.442

0.351 24578.178

0.468 32548.811

0.585 40376.121

0.702 48169.488

From the data in Table 9 above, it can be seen the value of base shear concrete structure for dynamic

nonlinear time history earthquake load with initial earthquake acceleration of 0.234g is 43935.725 kN and

increases in accordance with the increase in earthquake acceleration.

In the steel structure of the E ITERA building for nonlinear dynamic earthquake load time history with an

initial earthquake acceleration of 0.234g obtained a dynamic base shear value of 16419.444 kN. Likewise,

so on when an initial earthquake acceleration occurs (as can be seen on

Table 10).


This basic shear force is the result of dynamic shear force analysis with the most dominant loading

combination of time history combination. And from the two data above, it can be concluded that the

dynamic base shear of the concrete structure and steel structure is affected by an increase in the initial

acceleration of the earthquake (Aog). In addition, the base shear values of concrete structures that are larger

than steel structures will cause the cost of the lower structures to be more expensive because of the need

for a stronger lower structure (for the same soil conditions).

5 . Conclusions This study describes leveling time history method in analyzing the behavior of concrete and steel structures

in Gedung E ITERA. This method is by increasing the time history earthquake load that has been matched

with spectrum response of Gedung E ITERA (South Lampung ), so that the structural response can be seen

gradually. In this case the structural behavior that is reviewed are mass participation, plastic design,

displacement, rotation and base shear. In addition this method can be used to predict which structures are

prone to failure in receiving dynamic nonlinear time history load.

6. References

[1] Anonim. 1991. Standar SK SNI T-15-1991-03. Tata Cara Rencana Penghitungan Struktur Beton

untuk Bangunan Gedung. Bandung: LPMB Dep. Pekerjaan Umum RI.

[2] Anggen, Wandrianto S. 2014. Evaluasi Kinerja Struktur Gedung Bertingkat Dengan Analisis

Dinamik Time History Menggunakan Etabs Studi Kasus: Hotel Di Karanganyar [skripsi]. Teknik

Sipil, F. Teknik, Universitas Sebelas Maret.

[3] Bolton, W. 1998. Engineering Materials Technology. 3rd Edition. Butterworth-Heinemann,

England.

[4] Budiono, Bambang dan Lucky Supriatna. 2011. Studi Komparasi Desain Bangunan Tahan Gempa.

Bandung : ITB, ISBN.

[5] Chopra, A. K. 2011. Dynamic of Structures Theory and Applications to Earthquake Engineering:

Pearson.

[6] Departemen Pekerjaan Umum, 1983. Peraturan Pembebanan Indonesia Untuk Bangunan Gedung

(PPIUG 1983), Bandung: Yayasan Lembaga Penyelidikan Masalah Bangunan.

[7] FEMA-356. 2000. Prestandard and Commentary For The Seismic Rehabilitation Of Buildings.

Virginia. American Society of Civil Engineers.

[8] Imran, I. dan Hendrik, F. 2010. Perencanaan Struktur Gedung Beton Bertulang Tahan Gempa.

Bandung: Penerbit ITB.

[9] Paz, Mario. 1996. Dinamika Struktur Teori & Perhitungan terj. Manu A. P. Jakarta: Erlangga.

[10] Qamaruddin, Shaik. 2017. “Seismic Response Study Of Multi-Storied Reinforced ConcreteBuilding

with Fluid Viscous Dampers”. Tesis. Master Engineering, Civil Engineering, Chaitanya Bharathi

Institute of Technology.

[11] SNI 1726:2012, 2012, Tata Cara Perencanaan Ketahanan Gempa untuk Struktur Bangunan

Gedung dan Non Gedung. Badan Standarisasi Indonesia, Jakarta.

[12] SNI 1727:2013, 2013, Beban Minimum Untuk Perancangan Bangunan Gedung dan Struktur Lain.

Badan Standarisasi Indonesia, Jakarta.

[13] SNI 1729:2015, 2015, Spesifikasi Untuk Bangunan Gedung Baja Struktural. Badan Standarisasi

Indonesia, Jakarta.

[14] SNI 2847: 2013, 2013. Persyaratan Beton Struktural Untuk Bangunan Gedung. Badan Standarisasi

Indonesia, Jakarta.

[15] Ulfah, Atika. 2011. Evaluasi Kinerja Struktur Gedung Kuliah Umum Sardjito. Magister Teknik

Sipil, Universitas Islam Indonesia. Yogyakarta.

[16] Widodo. 2001. Respon Dinamik Struktur Elastik. UII Press. Yogyakarta.

Date post:	20-Jun-2020
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times

Behavior Analysis of Concrete and Steel Structure with...

Documents