The contracting experiments were conducted on 69 concrete prisms, which include 5 different strength grades, 2 curing conditions, and 2 humidity environments, and experimental data of concrete shrinkage for 589d were ...
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Wireless sensor technology-based structural health monitoring (SHM) has been widely investigated recently. This paper presents the new developments and applications of compressive sensing (CS) for wireless sensors and...
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The rapid construction nature and outstanding self-centring ability make the post-tensioned precast segmental (PTPS) bridge pier a promising alternative to traditional cast-in-place piers. In this paper, PTPS piers re...
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In this paper, the influence of mineral admixtures on the rheological properties of fresh Self-Compacting Concrete (SCC) mixture was studied using a new type of concrete rheometer. The results show that both yield she...
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An experimental study is conducted on fully grouted reinforced masonry shear walls (RMSWs) made from concrete blocks with a new configuration. Ten RMSWs are tested under reversed cyclic lateral load to investigate the...
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An experimental study is conducted on fully grouted reinforced masonry shear walls (RMSWs) made from concrete blocks with a new configuration. Ten RMSWs are tested under reversed cyclic lateral load to investigate the influence of different reinforcements and applied axial stress values on their seismic behavior. The results show that flexural strength increases with the applied axial stress, and shear strength dominated by diagonal cracking increases with both the amount of horizontal reinforcement and applied axial stress. Yield displacement, ductility, and energy dissipation capability can be improved substantially by increasing the amount of horizontal reinforcement. The critical parameters for the walls are derived from the experiment: displacement ductility values corresponding to 15% strength degradation of the walls reach up to 2.6 and 4.5 in the shear and flexure failure modes, respectively; stiffness values of flexure- and shear-dominated walls rapidly degrade to 17%–19% and 48%–57% of initial stiffness at 0.50 Dmax (displacement at peak load). The experiment suggests that RMSWs could be assigned a higher damping ratio (～14%) for collapse prevention design and a lower damping value (～7%) for a fully operational limit state or serviceability limit state.
Global failure mechanism, i.e., the strong-column weak-beam mechanism, can provide higher total energy dissipation capacity with less ductility demand on components than other failure modes, and results in a more unif...
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Global failure mechanism, i.e., the strong-column weak-beam mechanism, can provide higher total energy dissipation capacity with less ductility demand on components than other failure modes, and results in a more uniform story drift distribution and higher resistance to earthquake loads at the system level. However, the current code-based elastic design method cannot guarantee the global failure mechanism of frame structures under severe earthquakes. In this paper, a simple, but practical design procedure is proposed to ensure the global failure mechanism of reinforced concrete(RC) frame structures by redesigning the columns using the column tree method(CTM). CTM considers the yield limit state of all beams and column bases. The code-based design is firstly carried out to determine the section information of all beams and base columns. Then, the internal force demands applied on the column tree can be derived. Lastly, the column moments, shear forces and axial forces are determined according to the free-body diagram of CTM to finish the column redesign. Two RC frame structures with 6 and 12 stories are illustrated to verify the design procedure. The analytical results demonstrate the proposed approach can realize the global failure mechanism.
Recently, d36-type piezoelectric wafers derived from lead magnesium niobate-lead titanate (PMN-PT) single crystal materials have been proposed for elastic wave generation in thinwalled structures. In contrast to tradi...
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ISBN:
(纸本)9781510827936
Recently, d36-type piezoelectric wafers derived from lead magnesium niobate-lead titanate (PMN-PT) single crystal materials have been proposed for elastic wave generation in thinwalled structures. In contrast to traditional d31 piezoelectric materials which generate symmetric and anti-symmetric Lamb waves, d36 introduces these same Lamb waves plus an inplane shear horizontal (SH) wave. Based on guided wave theory, the SH0 wave mode is nondispersive which may find many advantages uses in structural health monitoring. To detect and localize damage (e.g., cracks, corrosion) in thin walled structures, a phased array of d36- type piezoelectric wafers is proposed. To validate the proposed phase array, extensive experiments have been conducted using an aluminum plate with four d36 PMN-PT piezoelectric wafers surface bonded. The d36 phased array is shown capable of accurately detecting the location of local damage in the plate. Good detection accuracy is observed indicating that this proposed methodology has the potential to provide an effective identification of damage in metallic thin walled structures.
By bond-anchorage property tests at 20°C ~500°C, the distribution of shear stress between carbon fiber sheets and concrete at all levels of loading and anchorage lengths were measured, which means the bond l...
By bond-anchorage property tests at 20°C ~500°C, the distribution of shear stress between carbon fiber sheets and concrete at all levels of loading and anchorage lengths were measured, which means the bond lengths during CFRP sheets are pulled off at the same time when the concrete is torn and stripped were gotten. The failure modes were obtained. In addition, the failure loads were measured, and the calculated formulas of anchorage lengths were identified by fitting at high temperature. It can be seen that the anchorage lengths of carbon fiber sheets increase with increasing temperature at 20°C ~100°C, the anchorage lengths of carbon fiber sheets decrease with increasing temperature at 100°C ~500°C. Tests prove that AASCM has favorable high-temperature resistant and bond anchorage properties.
Due to its design versatility, availability and cost efficiency, concrete continues to play a dominant role in the construction industry. However, the production of Portland cement, a primary component of typical conc...
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