Some related assessment Q's

[Shz713]

Hi all,

Recently I've been involved in assessment of bridges, but I found it takes some time to get familiar with the whole concept. Appreciate if anyone answer the below questions shortly/detailed:

1-when the weight of reinforcement is considered as dead load for assessment? Since when we account for DL and SDL,it is not included reinforcement.
2-for deck slab such as in case of box girder (top or soffit slab), how the deck slab is assessed? Such as figure shown below, whereby the primary reo for deck is transverse to traffic direction; do we assess it only for bending considering as singly reinforced section?

3-for carrying out virtual performance load test by software (to get the load-displacement curve), it is practical to consider a)fibre hinges at various locations determined from linear analysis and then incrementally increasing the load until failure or b)modelling reo and nonlienaruty in those critical regions and then incrementally adding up the static loads (i.e. wheel loads) till predefined displacement/complete failure occurs.

4- I read in an assessment report that a 2*3 pile cap was assessed in transverse direction using strut and tie method, while in longitudinal direction was treated as beam (and only was checked for shear at face of pier), why?

Cheers,



Shoot for the Moon, even if U miss, U still land among Stars!

 

[bridgebuster]

1. Typically in concrete design we don't account for the weight of rebar in the DL & SDL calculation. Although - it's been some years since I designed a box beam - I recall on a project we did account for the weight of the tendons.

2. The deck can be treated as a continuous beam for reinforcing design. The transverse bars are the main reinforcement.

3. No comment; modelling is not my thing.

4. Strut & tie in the transverse direction makes sense. Maybe in the longitudinal direction the pile cap was too narrow to develop a model. Without seeing a drawing I can only speculate. Normally in a pier cap bending in the longitudinal direction won't control but there are usually high shear forces near the pier.

 

[Shz713]

Thanks for your response, I've attached the pile cap details but not very clear (I had to scan over printed pages)

Shoot for the Moon, even if U miss, U still land among Stars!