Study on an Optimal Strut-And-Tie Model for Concrete Deep Beams

Haitao Chen,Lai Wang,Jitao Zhong

doi:10.3390/app9173637

Haitao Chen, Lai Wang + Show 1 more

Open Access

https://doi.org/10.3390/app9173637

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Abstract

The optimal strut-and-tie models (STMs) of two typical irregular concrete deep beams were constructed using evolutionary structural optimization and compared with those of previous studies. The reinforced concrete deep beam specimens were cast according to the reinforcement designs guided by different STMs. Eight irregular concrete deep beam specimens were experimentally investigated under stepped loading, and the differences in the amount of steel used, the load-carrying capacity, and the failure pattern of the different specimens were analyzed. The results show that the optimal STMs proposed in this study have significant advantages in terms of cost-effectiveness and can simultaneously ensure the load-carrying capacity, delay the crack propagation of irregular concrete deep beams, and reduce the amount of steel used in structural members. Therefore, they have an important engineering application value for the reinforcement design of irregular concrete deep beams.

Highlights

As one of the main load-carrying structural members, reinforced concrete deep beams have been widely used in bridge structures, high-rise buildings, and underground structures
The stress distribution is uneven inside an irregular concrete deep beam, especially at the load points or near abrupt geometrical changes, where the stress distribution is disorderly and dense, causing the Bernoulli hypothesis to be obviously invalid and the design theory based on the plane section assumption to no longer be applicable
An experimental study was conducted on the strut-and-tie model (STM) of irregular concrete

Summary

Introduction

As one of the main load-carrying structural members, reinforced concrete deep beams have been widely used in bridge structures, high-rise buildings, and underground structures. Chen et al [5] and Novak et al [6] constructed optimal STMs for concrete deep beams with variable cross sections and openings and concrete deep beams with rectangular openings according to ACI 318-02 [7]. They tested the corresponding concrete deep beam specimens. Their results showed that the STM method can be used for the conservative design of irregular concrete deep beams.

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