The composite steel reinforced concrete (SRC) columns have been widely used in Structural Engineering due to their good performances. Many studies have been done on the SRC columns' performances, but they focused on the ordinary types with conventional configurations and materials. In this study, nine new types of steel reinforced lightweight aggregate concrete (SRLAC) short columns with cross-shaped (+shaped and X-shaped) steel section were tested under monotonically axial compressive load; the studied parameters included steel section ratio, steel section configuration, ties spacing, lightweight aggregate concrete (LWAC) strength, and longitudinal bars ratio. From the results, it could be found that the specimens with larger ties ratio, concrete strength, longitudinal bars ratio, and steel section ratio achieved great strength and stiffness due to the excellent interaction between the concrete and steel. The well-confined concrete core could strengthen the steel section. The ductility and toughness of the specimens were influenced by the LWAC strength, steel section ratio, and longitudinal bars ratio; in addition, larger ties ratio with smaller LWAC strength led to better ductility and toughness. The load transfer between concrete and steel section largely depends on the LWAC strength, and the ultimate strength of the new types of SRLAC short columns could be approximately predicted, referring to the codes' formulas of ordinary types of steel reinforced concrete (SRC) columns. Among the used codes, the BS-5400-05 led to the most conservative results.

To achieve a rational detail of the girder-abutment joints in composite integral bridges, and validate the performance of the joints with perfobond connectors, this paper proposes two innovative types of I-shaped steel girder-concrete abutment joints with perfobond connectors intended for the most of bearing capacity and the convenience of concrete pouring. The major difference between the two joints is the presence of the top flange inside the abutments. Two scaled models were investigated with tests and finite element method, and the damage mechanism was revealed. Results show that the joints meet design requirements no matter the top flange exists or not. Compared to the joint without top flange, the initial stiffness of the one with top flange is higher by 7%, and the strength is higher by 50%. The moment decreases linearly in both types of the joints. At design loads, perfobond connectors take about 70% and 50% of the external moment with and without top flange respectively, while at ultimate loads, perfobond connectors take 53% and 26% of the external moment respectively. The ultimate strengths of the reduced sections are suggested to be taken as the bending strengths of the joints.

In order to study the interfacial bond-slip behavior of steel reinforced recycled concrete (SRRC) under cyclic loading, thirteen specimens were designed and tested under cyclic loading and one under monotonic loading. The test results indicated that the average bond strength of SRRC decreased with the increasing replacement ratio of recycled concrete, whereas the bond strength increased with an increase in the concrete cover thickness, the volumetric stirrup ratio, and the strength of recycled concrete. The ultimate bond strength of the cyclically-loaded specimen was significantly (41%) lower than that of the companion monotonically-loaded specimen. The cyclic phenomena also showed that SRRC specimens went through the non-slip phase, initial slip phase, failure phase, bond strength degradation phase and residual phase, with all specimens exhibiting basically the same shape of the bond-slip curve. Additionally, the paper presents the equations that were developed to calculate the characteristic bond strength of SRRC, which were verified based on experimental results.

Presented are experimental results from 24 full-scale push test specimens to study the behaviour of composite beams with trapezoidal profiled sheeting laid transverse to the beam axis. The tests use a single-sided horizontal push test setup and are divided into two series. First series contained shear loading only and the second had normal load besides shear load. Four parameters are studied: the effect of wire mesh position and number of its layers, placing a reinforcing bar at the bottom flange of the deck, normal load and its position, and shear stud layout. The results indicate that positioning mesh on top of the deck flange or 30 mm from top of the concrete slab does not affect the stud\' s s strength and ductility. Thus, existing industry practice of locating the mesh at a nominal cover from top of the concrete slab and Eurocode 4 requirement of placing mesh 30 mm below the stud\' s head are both acceptable. Double mesh layer resulted in 17% increase in stud strength for push tests with single stud per rib. Placing a T16 bar at the bottom of the deck rib did not affect shear stud behaviour. The normal load resulted in 40% and 23% increase in stud strength for single and double studs per rib. Use of studs only in the middle three ribs out of five increased the strength by 23% compared to the layout with studs in first four ribs. Eurocode 4 and Johnson and Yuan equations predicted well the stud strength for single stud/rib tests without normal load, with estimations within 10% of the characteristic experimental load. These equations highly under-estimated the stud capacity, by about 40-50%, for tests with normal load. AISC 360-16 generally over-estimated the stud capacity, except for single stud/rib push tests with normal load. Nellinger equations precisely predicted the stud resistance for push tests with normal load, with ratio of experimental over predicted load as 0.99 and coefficient of variation of about 8%. But, Nellinger method over-estimated the stud capacity by about 20% in push tests with single studs without normal load.

This paper proposed an innovative RC column with encased prefabricated high-strength concrete filled steel tube core, and four RC columns with encased prefabricated high-strength CFST core and a RC control-column were tested under lateral low cyclic loading. All specimens were evaluated by the cracks developments, failure patterns, hysteretic behavior, skeleton curves, strength and stiffness degradation, ductility and energy dissipation capacity. The effects of stirrup ratio and welding studs of prefabricated CFST core were investigated in details. The experiment results indicated that compared with the RC control-column, the performances of RC columns with encased prefabricated high-strength CFST core, including the hysteretic behavior, strength degradation, ductility and energy dissipation, were significantly improved. Higher stirrup ratio of the RC column with encased prefabricated high-strength CFST core leaded to higher ductility and more satisfactory energy dissipation capacity, stiffness degradation. Studs could effectively combine prefabricated high-strength CFST core and surrounding concrete, which significantly increase the integrity of RC column with encased prefabricated high-strength CFST core. Based on the test results, a numerical model was established to further analyze the cyclic behavior of the test specimens, and the numerical results agreed well with the test results, which showed the feasibility for the further parametric study. Finally, on the basis of the plastic stress theory, a calculation model for seismic bending moment capacity of RC column with encased prefabricated high-strength CFST core was established, and the results obtained form the formulas showed good agreement with the experiments.

The deflection of composite (cellular) beams is important for serviceability purposes. However, the available methods to predict the deflection are inaccurate. This research aims to propose a method for predicting the deflection with improved accuracy. The proposed deflection consists of contributions from overall flexural behavior and Vierendeel bending. In addition to the slip action, a reduction factor for computing the effective moment of inertia is investigated and used to compute the flexural deflection. The Vierendeel deformation was determined based on shear deflection of a virtual cantilever beam. No local composite action is conservatively assumed in the cantilever beam. Over 700 three-dimensional finite element (FE) models were simulated to investigate the reduction factor and limitations of the proposed method. The FE model was validated against 13 experimental load-deflection curves from the literature. The proposed method is suitable for predicting the deflection of composite cellular beams having the spacing ratio 1.35 or higher and the span ratio higher than 5. For such cases, the deflection estimate is from 0.90 to 1.05 times the FE deflection. The web-post deformation and the global shear deflection affect the prediction accuracy. In comparison to other methods, the proposed method is more accurate in predicting the deflection.

The present research aims to analyze the response of viscoelastic laminated composite microplate under microparticle low-velocity impact. Hertz contact law is used to model the impact phenomenon between the microparticle and the microplate. According to Kelvin-Voigt theory, the realistic behavior of the structure is considered by considering the viscoelastic properties. The governing equations of the system are derived based on the first-order shear deformation plate theory (FSDT) and the nonlocal strain gradient theory (NSGT) by employing Hamilton's principle. Galerkin's method is employed to solve differential equations of microplate with different boundary conditions. Afterward, the system of time-dependent equations by applying the Newmark' s method is solved. The parametric study is presented to examine the effect of particle radius, particle initial velocity, nonlocal parameter, length scale parameter, viscoelastic modulus, fiber orientation, and different boundary conditions on the impact response of microplate.

Soil nailing is one of the most common and important techniques to exchange conventional retaining systems for deep excavation. This approach contains a significant saving in cost and time of construction compared to conventional retaining systems. In this paper, an attempt has been made to evaluate the dynamical response of a deep vertical excavation on ground of 8 m height using soil nail wall. It has been tried to investigate the effects of different modeling approaches on the dynamic response of soil-nailed walls by considering the three behavioral methods; Mohr Coulomb (MC), hardening soil (HS) and hardening soil model with Small-Strain stiffness ensued from small strains (HSS). Nonlinear time history analysis has been implemented to compare the displacements under the sinus excitation with 0.5, 1, and 1.5 Hz with PGA= 0.3 g. Different points along the height of the wall are selected and considered. At the last part of this paper, incremental dynamic analysis (IDA) was implemented to the soil nail wall to consider the effect of the different earthquake records on the response of the wall. The IDA curve is also presented for the considered soil nail wall.