Vehicle Loadings in CSiBridge

[Shz713]

Hi all,

When we want to study the effect of vehicular loading on bridges, we examine by using some design vehicles such as those specified by AASHTO guideline. Some of these design vehicles need to maintain a specified distance (for example 600mm) from curb to travel along the centerline of bridge to produce most onerous effect.

I'd like to know how such user-defined distances can be implemented in CSiBridge. I tried to change the Minimum distance allowed from wheel axel load when defining the vehicle in software. But when I check the maxmoment/make animation of movement, there's no change in the moevement of vehivcle.

Anyone has experience on this?

Thanks ahead

 

[TehMightyEngineer]

I'm not familiar with CSiBridge but can you change the bridge lane width definition and force the bridge to be considered single lane? I would think the software would then center the vehicle loads on the bridge.

Maine Professional and Structural Engineer
American Concrete Industries

http://www.americanconcrete.com

 

[BridgeEI]

Are you talking movement laterally from the curb or longitudinally?

Depending on the girder you're looking at, the distribution factor will change so you should see a change in moment for the exterior girder. The interior could stay the same.

I'm not familiar with this program so take it for what it's worth. I would check the distribution factors first to see if they are changing and if not, determine why.

 

[Shz713]

Thanks all for replying.

I did as follow:

Defined two lanes having width of 4 m and eccentricity of 2.15 with bridge centerline(15+15 cm from both lines to account for the gap exist in the real road). For right lane, I defined the right edge as exterior and left edge (which is next to bridge centerline) to be interior. Then I did same for left line but vise-versa (since vehicle is approaching from other direction).
When defining vehicle, there's is an option to allow minimum distance from wheel axle load for both interior and exterior edges. I inserted different values for different scenarios; however, the output was same (for instance the moment envelope for all girders changed marginally by decimal point only when considering different distance between wheel and edges).

So now I'm perplexed to how to implement various movement scenarios in software. Here in Australia we use TMR assessment criteria which says if carriageway is between 6.3-9m then the vehicles should be placed on bridge centerline, 0.6m away from kerbs and 3.1m within any transverse location. To simulate such criteria, I believe I have to change the distance from the edges but unluckily it's not working.

Even if someone could tell me the concept of applying different vehicle positions to get most severe effect using different software still is fine. I just need to grasp the idea then I figure it out in CSiBridge.

Peace