A Study on Development of Live Load Model for Passenger Vehicles-only Bridges

A Study on Development of Live Load Model for Pass

enger Vehicles-only Bridges

Korean Expressway Corporation

Choi Hyeok-jin

(Structure Engineer, PE)

CONTENT

S

1. Background

2. Road Specifications

3. Governing Factors

4. Specification Development

A Study on Development

of Live Load Model for

Passenger Car-only

Bridges

1.1 Benefits of Designated Highways

1.2 Benefits of Passenger vehicles-Only Roads

1. Background

Korean Expressway Corporation / Design Evaluation Division

Designated Road

Safety

Economical

Efficiency

Public dissatisfaction

Complex design issues

1. Background


Car Only Highways

Road Barriers

Straight roads for higher speeds

Overpass construction

Less Road Accidents

Faster Travel Times

More comfortable for long distances

1. Background


1. Background

Passenger Car/ Truck Comparison

Passenger Car Heavy Trucks


Passenger Vehicle

Small Size

Agility

Speed

Smaller Lanes

Lower Height Clearances

Lighter Loads

Uniformity of Speed

Benefits of Passenger Vehicle Only Roads

1. Background


0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

1 Ton or Less

88.5%

Korean Vehicles By Weight

Passenger

Cars

76.1%

1. Background


Traffic Statistics

Vehicle Ratios

Urban Areas

All Roads

Heavy Trucks

Passenger Vehicles

(73%)

Heavy Trucks

Passenger Vehicles

(90%)

교통혼잡 비용 (조원)

0

5

1 0

1 5

2 0

2 5

3 0

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

10%

Cost of Traffic Jams

Cost of Traffic Jams to the Korean

Economy = US$ 19,000,000,000

1. Background


Acquiring Land (Currently in Use)

Land Prices (Appropriation)

Environmental Impact

Public Inconvenience

Problems of New Road Construction

1. Background

Smaller roads avoid many of these problems


2.2 Examples of Passenger

Car Only Roads

2.3 Road Specifications

2 Road Specifications


International Examples(1)

Abstract;• Paris Ring Road

• A86 Highway

• Smart Tunnel • Fuxing Donglu

Tunnel

Speed limitV=70km/h

2 lanes/2 levels

V=60km/h

2 lanes/2 levels

V=40km/h

2 lanes/2 levels

length4 lanes

(10.0km)

4 lanes

(3.0km)

4 lanes

(2.8km)

Period of

construction1997~2010 1995~2007 2002~2004

France

(Under construction)

China

(public service)

Malaysia




International Examples(2)

cross

Section

Road width 8.7m 8.85m 7.0m

Lane width 2.8m 3.25m 3.0m

vertical

Clearance2.55m 2.55m 2.60m

Construction

methodTBM TBM, NATM, SHIELD SHIELD

France


China

(public service)

Malaysia

(Under construction)횡단면도 횡류식 적용

- 급기 환기소 : 4개소

- 배기 환기소 : 4개소

환기

방식

횡단면도 횡류식 적용

- 급기 환기소 : 4개소

- 배기 환기소 : 4개소

환기

방식



Korean Examples

Design

speed

Lane

width

Vertical

Clearance

shoulder

left right

70km/hr 3.0m 3.0m 0.5m 2.0m

• 표준 폭원 및 시설한계

map

projectSeobu highway

(Soengsan Bridge~Anyangchun Bridge)

Cross

section2 lanes/2 levels

length 11.9km

800950 9.250

11.000

1.0

00

[email protected]=6.000 2.000500

3.0

00

20

0

8.500

250

150

500

90

01

.10

03

.20

0

5.2

00

1.0

00

800 9509.250

11.000

1.0

00

[email protected]=6.0002.000 500

3.0

00

20

0

8.500

250

150

500

1.0

00

VAR.

※민자사업으로 제안된 사업(사업 시행여부 미확정)



Allowable Car Specifications

Passenger

Car1,000cc less 1,500cc less 1,500~2,000cc less 2,000cc or over

Bus 1,000cc less under 15 people under 35 people 36 people or over

Truck 1,000cc less

Load capacity under 1

ton

loaded weight under 3.5

ton


ton

loaded weight under 10

ton


ton

loaded weight 3.5 ton or

over

Special

Vehicle1,000cc less

loaded weight under 3.5ton

loaded weight under 10ton

loaded weight under 10ton or over

division1 division2 division3 division4



Allowable Special Vehicles

Pump Truck

7.08ton

Small Tanker

10.73ton

Snow Plow

10.2tonRoller

8.8ton

Extension Arm

6.9ton

These vehicles, still under

12 tons, can be on the road,

but only when all other cars

are vacated from the lane.



Road Specifications For

Passenger Cars

Design Vehicle Dimensions

speed limit : over100km/hr on highway

width Height LengthWheel base

Overhang Turning radiusFront Rear

2.0 2.8 6.0 3.7 1.0 1.3 7.0

unit : m

maximum slope: 1~2% more than common roadways

Design Speed Flat area Mount area

100km/hr 4% 6%

80km/hr 6% 7%

60km/hr 7% 9%

Verical Clearance: 3m [car height(2.8m)+extra(0.2m)



3.1 Goal of Live Load Model Development

3.2 Principal Factors of Live Load

3.3 Procedure for Development of a Design Live

Load Model



A constant safety rate across all span lengths

Goal of Live Load Model Development


Development of economically feasible safe load that

befits bridge life cycle.

Load patterns that are easy to use in design

process, and are familiar to designers.


Principal Factors of Live Load

Distance between vehicles (= 1.2m)

Load distribution of axle load

Vehicle type [passenger car, truck]

Vehicle weight [vehicle + load weight]

Compounding affect of vehicles in tandem



Passenger car Truck

Principal Factor of Live Load

Type/Weight of Vehicle

Compounding affects of vehicles in tandem



Survey of vehicle loads and driving patterns

Determine the trend line by Probability Chart

Estimate maximum load effects by span length

Determine design live load

Procedure for Development

of a Design Live Load Model



4.1 driving patterns

4.2 Maximum load effect

4.3 Live load model

4.4 economical benefits



• WIM ; Weigh-In-Motion

- Loop Sensor : measures axle

lengths

- Piezo Sensor : measures vehicle

speed, weight , and number of axles.

Loop Sensor Piezo Sensor

Data

Locker

WIM System

Survey of Vehicle Loads

• Location : Central Inland Highway(South bound ,Yeoju JCT ~ Janghowon IC)

• Vehicles : Passenger car/ 1 ton truck (total 60,494 vehicles)

※ WIM system allows a more

accurate weight for smaller

vehicles.



Driving Pattern Survey

(mixture rate/tandem rate)• Location : Pangyo IC~Singal JCT, Topyeong IC~Namyangju IC

• Vehicles : Passenger car/ 1 ton truck (total 43,973 vehicles)

Survey of Driving Patterns

※We must discover the passenger car/truck mixture when travelling

in tandem.



• using top 10%, 20% values

from weight survey data

• using the Gumbel Probability

Chart

- an equation can convert

probability distribution to a one-

dimensional linear formula

• Trend Line(y=a+bx)

y=Gumbel probability

x=weight

Trend Line Sample

Chart

Estimating Maximum Load Effects (1)


Maximum Load Effects by Largest single vehicle


Groups of vehicles running in tandem

- different types running in tandem

– same types of vehicles running in tandem

P

P

T

T

18,185 1,301

1,301 193

0.84120 0.06018

0.06018 0.00893

Using a Marcov Chain



Maximum Load Effects by Vehicles in tandem


Largest single vehicle

Calculating load effects at variable span lengths (positive moment, shear, and negative moment)


Vehicles in tandem

Vehicles in tandem



Bias factor of positive moment

In order to ensure a constant safety rate over variable span lengths we use

a Bias factor calculation(M75/MDESIGN)

Constant

safety rate

Bias Factor



•uniformly distributed load + concentrated load.

※ span length 10m : 12ton vehicle allowable

※ span length 30m : 15ton vehicle allowable

Design Live Load



Comparison of Costs with Regular Road

Superstructure is 20 – 27% cheaper.

DB-24, DL-24 CL-3.5

2.3

m2.7

m

Sample bridge : PnP

bridge

Less road width

# of girders 5 ⇒ 4

Cost savings of 18%

Lighter Load

height: 14.8% less

concrete: 18.5% less

rebar : 9.6% less

Cost savings of 7%



Benefits of Passenger Car Only Roads are that they are

cheaper, smaller, and safer than regular roads.

Passenger Car Only roads are needed because of urban

area overdevelopment and high land costs in cities.

Estimating maximum load effects for both categories,

greatest load and groups of vehicles running in tandem, using

span lengths from 10 meters to 100 meters.

Summary 1

Date post:	05-Jul-2015
Category:	Education
Upload:	hyeok-jin-choi
View:	808 times
Download:	4 times

A Study on Development of Live Load Model for Passenger Vehicles-only Bridges

Education