abdulqadeer29

I think there is a conversion mistake . 87.5mm x0.1= 8.75 cm.This should be the maximum limit of inter-story drift.

Thanks...I hope it will work . I will get back to this forum if i need further help.This idea will make our work easy.

This demand of increasing the strength is not based on design requirement or compressive strength requirement. it is purely based on getting long term durability against abrasion effect of flowing water with heavy sediment loading.This demand is not from designer 's end , but it is from the lenders technical advisers therefore our own firm is reluctant to increase the strength to 50 MPA.

ACI 224R writes: " For interior concrete , the lowest practical strength should be specified to reduce the cement content.This will reduce the heat of hydration and the consequent thermal gradient , decreasing the likelihood of cracking.More than the necessary amount of cement is detrimental rather than advantageous."

High strength concrete strength is 50 MPA. Before this, original design was based on 35 MPA that we considered as normal strength concrete. your second suggestion is already incorporated. The current design have only one layer with 50 MPA strength. 373 WEIR CROSS SECTION (12OF38).pdf 400 WEIR PIER REINFORCEMENT ARRANGEMNET (1OF13).pdf

What could be the damaging impact OF HIGH STRENGTH CONCRETE especially in water retaining structures like dams and spillways.It has been observed that designers mostly propose external 1 meter layer of such structures of high strength concrete as compared to inner one. One of the obvious reason is to ensure economical design and to avoid thermal cracking .High strength concrete provides long term durability ad effective resistant to abrasion. But the worrying point is such kind of difficult arrangement in a reinforced pier cause delay in the progress as well as require special form work. I am searching for some relevant references that describes the negative impact of using high strength concrete.

Thanks a lot Sir, for providing these valuable information.......

Thanks for your valuable guidance.Can you provide a reference which allows us to pour successive slab within 24 hours in case of concrete tunnel linings.? As our project specifications don't provide any guideline related to concrete tunnel linings but still our consultant restrict us for 72 hours until next pour, applying the limit of mass concrete as carried out in weir structures.

THIS paper is good for joints but there is no mention of time duration between pouring of successive concrete especially in massive concrete.

According to a report:- "6-7 hours before the failure, when concreting was half way, the bolts in cross girder of the steel girders placed on cantilever pier cap sheared off. This apparently happened because of excessive deflection of the pier cap, over which these longitudinal girders were placed. Apparently, instead of trying to find out the reasons behind this bolt failure, instruction was given by the site in-charge to weld the bracing again and go ahead with concreting." but giving a look to the images of collapse bridge, it was quite a risk to go for such a design when we are aware of construction practices in south Asia ...there should be some alternative path for such cases for load. Kolkata_Flyover_Collapse.pdf

This truss bridge will be rested on side abutments..... However, the bride is no more cantilever as they abandoed this idea. Still I'm very much thakful for above replies to this topic and want to know answer of my basic question.

I have been given an assignment to design a cantilever steel truss bridge of 35 meter span. I have analyzed the model in SAP 2000. I am bit confused and want to know the basic transferring mechanism of forces in such structure.Point that is pinching in my head is that: " TRUSS members only transfer axial forces at joints,no moment." then how a cantilever truss bridge will transfer bending forces to its foundation ?? how fixed support will act in such case? How members of truss will transfer their deflection and bending phenomena to supports?

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