The Structural Design of Tall and Special Buildings

Yue, Qingxia; Ren, Xiaodan; Zhang, Xin

doi: 10.1002/tal.1379pmid: N/A

Underpinning is a key component in the structural moving process, especially for high‐rise buildings with gravitational loads. In this paper, a most commonly used 4‐sided wrapped underpinning joint with 2 underpinning beams and 2 coupling beams for the frame structures was investigated. Sixteen prototypes were tested considering different shear span‐to‐depth ratios, underpinning joint heights, reinforcement ratios, and so forth. The experimental results showed that the underpinning beams can fail in shear or flexure‐shear. The interface between the column and the beam is also prone to failure during the loading. Further, the bearing capacity can be greatly improved with decreasing of the shear span‐to‐depth ratio, whereas more damage may occur within the interface domain. In the numerical simulations, a damage–plasticity constitutive model was adopted, and the cohesive elements were used to model the old‐to‐new concrete interface between the column and beams. It was found that the numerical results agreed quite well with the experimental results. Thus, the proposed approach can be a useful basis for further analysis and optimized design of underpinning joints.

Sartaji, Parisa; Sarvghad Moghadam, Abdoreza; Ashtiany, Mohsen Ghafory

doi: 10.1002/tal.1380pmid: N/A

Damage observed following moderate to large earthquakes has shown masonry buildings are vulnerable to lateral shaking. The results of statistical analyses in Iran show that 90% of schools in the retrofitting list are unreinforced masonry buildings. A Practical Guideline for Seismic Rehabilitation of Masonry Schools has been published in Iran. This guideline proposed 2 retrofitting methods for retrofitting masonry schools: use of shear wall and shotcreting the perimeter of building. In the case of shear wall, their construction is usually expensive; there are less projects retrofitted by shear walls, and in most retrofitting masonry schools projects, perimeter shotcrete is used. The main aim of this study is offering recommendation to improve this guideline, resulting in more economical approaches. This study proposes including lateral resistance of masonry walls in resisting seismic loads and in the case of shear wall foundation proposes strip shallow foundation for concrete shear walls by including effect of rocking, sliding, and settlement response. It has been shown that with including masonry walls in lateral resistance of building, a considerable reduction in maximum drift occurred. Interaction of soil and structure by considered strip shallow foundation reduces the base shear and increases maximum drift of the building.

doi: 10.1002/tal.1328pmid: N/A

No abstract is available for this article.

Qiao, Shengfang; Han, Xiaolei; Zhou, Kemin

doi: 10.1002/tal.1381pmid: N/A

Brace has been used to improve structural seismic performance in reinforced concrete (hereafter called RC) frame extensively. However, the reasonable bracing configurations were not highlighted. And the brace buckling was not considered. Bracing configurations and seismic performance of RC frame with brace are studied in this paper. First, optimized bracing configurations of entire structures and 1‐story 1‐span structures are derived by topology optimization using truss‐like material model. Next, the structure models are simulated in OpenSees. Moreover, different bracing configurations are employed. Last, seismic performance and seismic response of RC frame structures with brace are discussed using static nonlinear analysis and dynamic time–history analysis, and brace buckling is considered. The numerical results indicate that more details for manufacturing or constructing can be presented by bracing configuration using truss‐like model. Further, the increase of structural strength and stiffness is more advisable in bracing configuration using topology optimization (hereafter called TPB), which corresponds to optimized result using entire structure than other configurations. The optimized bracing configuration based on 1‐story 1‐span structure is also beneficial within the prescribed conditions. Moreover, the brace buckling can decrease both strength and stiffness, and the buckling can also aggravate the damage extent than the brace without buckling.