Current Issue : October-December Volume : 2025 Issue Number : 4 Articles : 5 Articles
Pre-tensioned concrete T-beams with draped strands have been gradually promoted and used in bridge construction in recent years due to their advantages such as simple structure, efficient force distribution, and few defects. However, the current design codes exhibit conservative provisions for the calculation of the shear capacity of such beams under a small shear span ratio, which may lead to a large design value of beam web thickness. This is primarily due to insufficient experimental data. This paper details a full-scale experimental investigation on the shear failure mechanisms of two 30 m pre-tensioned concrete T-beams with draped strands, under a shear span ratio of 1, at which the shear capacity of the beams represents their upper limit. The specimens were tested to analyze their mechanical behavior, including load-deflection response, crack distribution, stirrup strain, and strand slip. The ultimate shear capacities of the test beams were 7107 kN and 6742 kN. To evaluate the applicability of current design codes, the experimental results were compared with theoretical predictions from five international design codes. The analysis revealed that the AASHTO code provided the highest upper limit of shear capacity for pre-tensioned concrete T-beams with draped strands, whereas the Chinese code (JTG 3362-2018) exhibited a significantly high safety factor of 4.09. These findings provide a basis for the optimized design of pre-tensioned concrete T-beams with draped strands and the determination of the upper limit of shear capacity....
This study aimed to propose a probability-guaranteed spectrum method to enhance the reliability of seismic building designs, thereby addressing the inadequacy of the current code-specified response spectrum based on mean fortification levels. This study systematically evaluated the fitting performance of dynamic coefficient spectra under normal, log-normal, and gamma distribution assumptions based on 288 ground motion records from type II sites. MATLAB(2010) parameter fitting and the Kolmogorov–Smirnov test were used, revealing that the gamma distribution optimally characterized spectral characteristics across all period ranges (p < 0.05). This study innovatively established dynamic coefficient spectra curves for various probability guarantee levels (50–80%), quantitatively revealing the insufficient probability assurance of code spectra in the long-period range. Furthermore, this study proposed an evaluation framework for load safety levels of spectral values over the design service period, demonstrating that increasing probability guarantee levels significantly improved safety margins over a 50-year reference period. This method provides probabilistic foundations for the differentiated seismic design of important structures and offers valuable insights for revising current code provisions based on mean spectra....
Bamboo is a fast-growing biomass material with excellent performance, making it a preferred choice for the development of green and low-carbon building materials. However, challenges such as combustibility and difficulties in processing and utilization persist. In this study, bamboo chips are wrapped in fiberglass cloth and cemented with magnesium oxychloride cement (MOC) to develop green, environmentally friendly, flameretardant, and carbon-storing bamboo-based composite panels. Firstly, the optimal ratio of the inorganic adhesive MOC was systematically investigated, and flue gas desulfurization gypsum (FG) was added to enhance its water resistance. The flexural strengths of the composite board in the direction of the bamboo fiber and that perpendicular to it were found to be 15.71 MPa and 34.64 MPa, respectively. Secondly, numerical simulations were conducted alongside plate experiments, analyzing the floor and wall made from the boards. The results indicate that since the fiber-reinforced bamboo board as a lightweight wall can meet the requirements for a two-story building, it does not satisfy safety standards as a floor slab due to the higher loads. Despite this limitation, the fiber-reinforced bamboo board shows promising application prospects as a green and low-carbon alternative....
The shear strength of a steel shear wall (SSW) is typically governed by the yield strength of the steel. However, changes in mechanical properties beyond yielding—particularly those related to steel hardening and the effects of gravity loads—are not yet fully understood. These factors are critical for accurately assessing the shear capacity of SSWs during seismic events. In the current study, a method to calculate the shear force–displacement curve of a steel shear wall while considering the compression effect is presented, which incorporates both steel hardening and gravity effects. The analysis derives strains in tensile strips undergoing shear deformation using a strip model. Corresponding stresses are then determined using the stress–strain relationships obtained from tensile tests of the steel. Furthermore, the vertical stress induced by gravity loads is modeled using a three-segment distribution proposed before. For each tensile strip, the tension field stress is calculated by accounting for reductions due to vertical stress and the influence of steel hardening through the von Mises yield criterion. This approach enables the development of a shear force–displacement curve, which is subsequently validated against results from an experimentally verified finite element model. The findings demonstrate that the pushover curves predicted by this method closely align with those obtained from finite element analysis. Notably, the results indicate that the shear strength provided by the CAN/CSA-S16-01 equation may be overestimated by approximately 4%, 9%, and 18% when the vertical compression stresses are 50, 100, and 150 MPa for a wall with a slenderness of 150, respectively....
This paper analyzes the performance of the TMD-Inerter for tall building damping. The analysis is performed by simulation to ensure ideal working behaviour of the inerter, i.e., the inerter produces a force in proportion to the relative acceleration of its terminals without any friction of real inerter devices such as fly wheels. For the study, the most realistic TMD-Inerter configuration is considered where the inerter is grounded to the TMD mass and the structural mass next to the TMD mass, i.e., the TMD-Inerter is installed in the top floor room of the structure. Approximate closed-form solutions for the tuning of the TMD-Inerter parameters are derived based on the characteristics of the inerter force. The resulting frequency response functions for different inertance ratios are compared to those of the classical TMD with same mass ratio. The results clearly demonstrate that the TMD-Inerter worsens the tall building damping compared to the classical TMD for the realistic situation that the inerter is grounded to the structural mass next to the TMD. There are two physical reasons why the inerter worsens the efficiency of the TMD. First, the inerter force is per definition in proportion to the relative acceleration of its two terminals, i.e., it is not in proportion to the damper mass (absolute) acceleration whereby it does not increase the damper mass. Second, for harmonic excitation the inerter force characteristics show negative stiffness behaviour which explains why the TMD stiffness must be designed by taking into consideration both the TMD physical mass and the inertance to ensure the correct tuning of the TMD-Inerter natural frequency....
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