Seismology
An-Najah National UniversityFaculty of EngineeringCivil Department
Effect of Earthquake on Foundation
submitted by:
Mohammad Khluof Mohammad Dwiekat
submitted to:Dr. Isam JardanahChapter One
Introduction
Preview The purpose of the project is to study the effect of the Dead Sea earthquake on subsurface soil layers below the foundation of a symmetrical building with varying number of floors.
Project ContentChapter Two: Introduction to Seismicity and Seismicity of PalestineChapter Three: EduShake Application and AnalysisChapter Four: Structural DesignChapter Five: Discussion and Conclusions
Chapter two
Introduction to Seismicity and Seismicity of Palestine
SeismologyIs the scientific study of earthquakes and the propagation of elastic waves through the Earth.
The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic, atmospheric, and artificial processes.
seismic wavesThere are three basic types of seismic waves in solids: - P-waves :Pressure waves or Primary waves the first waves appear on a seismogramS-waves: shear or secondary waves, appear later than P-waves on a seismograminterface waves: they are guided by the surface of the so Earth they can be much larger in amplitude than body waves.Palestine EarthquakePalestine, through generally considered to have moderate seismicity, is threatened by the Dead Sea Rift, which creates a series of active faults running the length of the countryActive Faults in PalestineIn our region and vicinity there are many faults, these faults are considerate to be active or semi active and these faults are:Dead Sea Faults. WadiAraba Fault.Northern Faults.Northern Red Sea Faults.Wadi Sirhan Basalt fault.Wadi Farah-Carmel Al-Jaleil Faults. South East Mediterranean Fault.Cyprus Zone Fault.Carmel Fault.
Nablus EarthquakeThe study shows that the damage of these earthquake mostly during the amplification of seismic waves near the surface layers.
And these earthquake caused by Dead Sea fault.Factors Effect on FaultsEarthquake fault length Effects.Earthquake Distance Effects.Rock Type Effects.Chapter Three
EduShake Application and Analysis
IntroductionThis chapter describes the method used to determine the site responses spectra at foundation level for dead sea earthquake using a software program called EduShake Also, this chapter summarizes the geotechnical condition of the proposed site, which is located in the city of Nablus
Characteristic of Site ConditionGeological Site The site lies in Nablus in Al-Duwwar zone. The ground surface is approximately flat with the western and northern part about 2 to 3 m higher than the rest of the site area. The surficial ground is covered with asphalt pavements and existing structures.
Soil profile
EdushakeChapter FourStructural AnalysisDescription
LocationThe site of the building is located in Nablus on a silt clay soil with bearing capacity (2kg/cm 2).Program AnalysisFormulation the model into 3D using analysis program (SAP2000.v14.2), which can provide static and dynamic with seismic analysis, and then the results from SAP are compared with manual solution.CodeThe code to be adopted in all the steps of the structure design is (ACI318M-08).
MaterialThe cylinder compressive strength at 28days, 'c=250kg/cm2The yield strength of steel bars, y=4200kg/cm2 (high strength steel).LoadsDead load (DL) due to the own weight of the building component (slabs, beams, columns, ets.).Super Imposed Dead load (SID) due to flooring tiles and plastering ets...
Live load (LL) due to moving loads expected through the function of the building.
Checks1. Compatibility
2. Equilibrium
Design of Mat FoundationSoil will be defined with bearing capacity as simple springs under the Mat Foundation asks = 40 (SF) qa (SI UNITS) = 40 (2.5) 20 = 20000 KN/m2.SF : Factor of Safetyqa : Bearing Capacity
Applied Force Pu = 1.4 (Force on Critical column).Resist Force Pu = (1.06) 'c Bo DBo : PerimeterD : Thickness of Mat
Chapter FiveDiscussion and ConclusionsEduShake Results and Conclusions
Sap ResultsStructural Elements
MAT THICKNESSCOLUMN DIMENTIONBEAM DIMENTIONSLAB THICKNESSFLOOR No.MLENGTH*WIDTH(M*M)DEPTH*WIDTH(M*M)Mnits0.40.40*0.400.30*0.350.140.60.30*0.300.30*0.350.180.70.50*0.500.30*0.350.1120.850.55*0.550.30*0.350.11610.6*0.60.30*0.350.120Table 5-1 Dimensions of Structural ElementsSap Analysis and ConclusionsPhilosophy of Analysisphilosophy depends on two branches to analyze the effect of the Response Spectrum on the Foundation at Critical points. Four points were chosen to represent the Mat Foundation.The Four points that taken into considerations are:1. Edge of Mat foundation point A6 and C6.2. Middle of Mat foundation point A4 and C4.
The study deals with three cases for each point as follows:Case1: Force and Moment at normal situation. (NS)Case2: Force and Moment at normal with earthquake (Response Spectrum) situation. (NS&RS)Case3: Force and Moment at earthquake (Response Spectrum) situation. (RS)
PointA4 (Edge)C4 (Middle)LoadForce (Ton)Moment (Ton.M)Force (Ton)Moment (Ton.M)4104.5078225.21.812129017.58.5371693179.439201602717.565- Point A4Figure 5-11 Floor Number VS Normal Situation and Normal Situation with Response Spectrum Force.
Figure 5-12 Floor Number VS Normal Situation and Normal Situation with Response Spectrum Moment.
Figure 5-13 Floor Number VS Response Spectrum Force.
Figure 5-14 Floor Number VS Response Spectrum Moment.
Point C-4Figure 5-15 Floor number VS Normal Situation and Normal Situation with Response Spectrum Force.
Figure 5-16 Floor number VS Normal Situation and Normal Situation with Response Spectrum Moment.
Figure 5-17 Floor Number VS Response Spectrum Force.
Figure 5-18 Floor Number VS Response Spectrum Moment.
RecommendationsSoil ImprovementThe characteristic of the soil can be improved in many ways, the most common way is compaction by adding base course with good characteristics and compact it.2. Mat FoundationThe effect of the earthquake can be reduced at the edges of the mat foundation by adding 20 cm reinforced concrete around the mat.
3. Height of the StructureDepend in the study of the soil in Al-Dawar at Nablus City, it is recommended that the height of the building around eight floor because the effect of the earthquake is minimum which is almost constant till eight floor, after that steep increase in the effect of the earthquake.
Thank youFor good listening
Figure 2-1 Main Faults in Palestine Region and Vicinity
