Shear tab connections are some of the most and simplest connections are used on steel constriction. The behavior of shear tabs under conventional loads are studied, but, the behavior of shear tabs become complex under companied loads axial and shear forces and moment. The connection should be sufficient ductile rotation to resist the unexpected force when the structures are exposed such as earthquake or wind load. The aim of this study is tested six steel portal frames. Three specimens are tested under horizontal cyclic load-quasi static load and other three specimens are verified under inclined cyclic load – quasi-static load. The connections of specimens are developed by using composites steel bolt/rubber are instead of conventional steel bolts for bolted the shear tab connections at the web of the beam. The composite steel bolts/rubber with different diameters are made of steel bolts covered by rubber taken from the old and wasted tires. Enhanced in the steel connections were cleared by increasing the resistance of these steel frames during the test as well as the tests are investigated that the effect of the inclined cyclic load is more influential than horizontal cyclic load.

This paper representsexperimental and numerical study the behavior of the rubberized steel frame connections. One single-bay, one-story without elastic buckling are cyclically tested. The experimental specimens are simulated and analyzed by the ABAQUS program. Four specimens of steel plane portal frame are investigated under horizontal reversed cyclic loads. The specimen connections are developed by using different diameters of composite steel bolts/rubberinstead of conventional steel bolts to connect the beams with columns. The yield and ultimate strength, ductility, envelope curves, and damping ratio of these specimens are analyzed and compared.  The finite element method is used to establish and verify the results of the laboratory test. The results of the experimental and numerical tests gave a large load-carrying capacity, reduction in the stresses, excellent ductility and energy dissipation capacity, and remarkably improved damping ratio.

Slabs punching shear capacity for normal strength concrete (NSC) and high strength concrete has been investigated in this paper. Due to the significance of concrete technology in the construction industry, more attention has been paid to high strength concrete in this paper. Then, detailed comparison is carried to evaluate the outcome by referring to several existing standards.Slabs punching tests have been collected from the reported results in the literature. Forty-seven tested slab specimens have been grouped from the available published information. In this work, the collected specimens are studied thoroughly, and a conclusion has been drawn from the preliminary investigation that punching shear failure is a common feature in the forty-seven specimens. The collected concrete slab specimens have diversified cylinder compressive strength (𝑓 𝑐 ′ ) ranged from 14.4 MPa to 119 MPa. However, the application of (𝑓 𝑐 ′ ) in existing codes is restricted to a limit as mention hereafter. American Concrete Institute (ACI-14) limits the practical application of 𝑓 𝑐 ′ to 69MPa, while The Australian Concrete Structures Standard (AS-94) limits 𝑓 𝑐 ′ to 50 MPa. The recent evolvement in concrete technology has made the production of HSC with 𝑓 𝑐 ′ much greater than the aforementioned values affordably reachable. Therefore, the present research attempts to bridge this gap and goes beyond the standards restrictions. This has been achieved by proposing a new design equation for punching shear through applying a regression analysis. The accuracy of the proposed equation and the existing equations have been examined by utilizing statistical analysis [Arithmetical mean (𝑥̅ ), Variation (VAR), Standard Deviation (SD) and Coefficient of Variation (COV)] to the punching shear failure strength values. The proposed method results for 𝑥 ̅ , VAR, SD and COV are 1.575, 0.364, 0.1299 and 23.128% respectively, and these are smaller when compared with the other 6 existing code methods.

No abstract

This study scoped to develop the connections of steel structures using composite steel bolts/rubber to connect beam-to columns joints of steel structures instead of conventional steel bolts. Four steel plane portal frames were tested under horizontal cyclic quasi-static load. The study included testing different diameters of composite steel bolts/rubber: 0.5dbolt , 1.0dbolt , and 1.5dbolt , that are used to connect the beam with columns and these results were compared with traditional beam-to columns connections without rubber. The rubberized connections are working at high structural standards through reducing the effect of the stresses resulting from the earthquakes by absorbing damping process. They protect the bolts that are used in joints of steel structures from corrosion due to friction, and they are economically feasible because the rubber that was used for covering the bolts is taken from old tires. The experimental tests proved that using the rubber material around the bolts as much as one - half times bolt diameter raises the specimen’s resistance by 166.66%, increases the displacement by 163.30%, and reduces the strain by 48.13%, as compared with bolts that do not have a rubber (steel bolts only). All these results will be discussed in detail in this report.