最新刊期
- 摘要：During prefabricated construction, the precise verticality adjustment of large prefabricated column components is critical to installation quality, construction efficiency, and operational safety. To address the limitations of conventional adjustment methods, which rely on manual crane operations and total station measurements and suffer from low efficiency, strong dependence on operator experience, and poor adjustment consistency, this paper proposes an integrated intelligent verticality control system for the installation of prefabricated column components. First, a mobile verticality measurement unit is developed using a high-precision laser rangefinder and an inclinometer to acquire the component's spatial attitude on site. Subsequently, the verticality deviation is calculated from distance measurements obtained at different elevation angles. A Kalman filtering algorithm is introduced to dynamically estimate the component attitude in the presence of environmental disturbances and measurement noise, thereby providing smooth and accurate inclination information. Finally, under the small-angle quasi-static assumption, an intelligent verticality adjustment strategy based on Active Disturbance Rejection Control (ADRC) is developed. A tension-threshold protection mechanism and a communication anomaly detection scheme are further incorporated to achieve fully automated closed-loop adjustment of the component posture. Field experiments demonstrate that the proposed system not only improves operational efficiency and adjustment consistency but also reduces the verticality deviation of prefabricated components to less than 10 mm, satisfying the practical requirements for efficient and high-precision construction of prefabricated metro stations.关键词：prefabricated cylindrical component;verticality measurement;active disturbance rejection controller;extended state observer1|0|0更新时间：2026-10-16
- 摘要：To address the difficulties in the construction of transmission tower foundations in mountainous areas, including the limited access of large equipment, the low degree of mechanization of traditional foundation types, and complex loading conditions, this paper proposes a novel composite structure consisting of crossed micropile groups and a shallow foundation. In this structure, the shallow foundation mainly bears compressive loads, while the micropile group resists uplift and horizontal loads. A “crossed pile-group effect” is formed through the rigid convergence of pile heads, and the structure is compatible with fully mechanized drilling using portable rigs. Through full-scale field tests, the effects of reinforcement ratio, inclination angle, pile diameter, curing age, and the number of bundled piles on uplift bearing performance were systematically investigated. A theoretical model of the pile-group effect based on the spatial union of failure cone surfaces was also established. The results show that shear failure of the soil around each pile occurred, and the bearing capacity was governed by the shear strength of the pile–soil interface. When the pile diameter increased from 150 mm to 200 mm, the bearing capacity increased by approximately 10.1%, while the cumulative displacement decreased by 42%. A small inclination angle of 5° reduced displacement by about 26% while maintaining nearly unchanged bearing capacity, and a 15° inclination angle further increased the bearing capacity by approximately 11.2%. Insufficient curing significantly reduced the bearing capacity because of the low elastic modulus and the weakening of the normal stress at the interface caused by the Poisson effect; therefore, the curing period in engineering practice should not be less than 28 days. The bearing capacity of the crossed bundled piles reached 1.36–1.40 times that of a single pile. This advantage was attributed to the synchronous mobilization of pile loads through rigid nodes and the combined compaction effect caused by the lateral squeezing of inclined piles, with the failure surface presenting an overall inverted frustum shape. The failure-surface volume union model modified by the construction disturbance coefficient agreed well with the test results and can provide a calculation tool for engineering design. The proposed structure combines high bearing capacity, high stiffness, and adaptability to mechanized construction in mountainous areas, making it a preferred foundation type for transmission towers in mountainous regions.关键词：transmission tower;crossed micropile group;uplift bearing capacity;theoretical model1|0|0更新时间：2026-09-22
- 摘要：To simultaneously improve the mechanical behavior, fire resistance, and constructability of partially encased composite beam (PEC beam), this study incorporates hybrid-fiber reinforced ultra-high performance concrete (H-UHPC) into partially encased castellated steel concrete composite beams and proposes a partially encased castellated steel H-UHPC composite beam (PECSHUC beam). To compare the effect of UHPC type, steel-fiber reinforced ultra-high performance concrete (S-UHPC) is also applied to partially encased castellated steel concrete composite beams, and one partially encased castellated steel S-UHPC composite beam (PECSSUC beam) is designed as a comparative specimen. Fire tests and subsequent post-fire static loading tests were carried out on five PECSHUC beams and one PECSSUC beam to investigate the effects of fire duration, the number of fire-exposed surfaces, and UHPC type on the surface damage, internal temperature distribution, and post-fire shear behavior of the composite beams. The results show that the incorporation of polyvinyl alcohol (PVA) fibers effectively suppresses explosive spalling of UHPC at elevated temperatures, thereby ensuring the integrity of PECSHUC beams under fire conditions. Fire duration and the number of fire-exposed surfaces have relatively pronounced effects on the internal temperature distribution and post-fire shear behavior of the specimens, whereas the influence of UHPC type is relatively minor. After fire exposure, all specimens with a shear span-to-depth ratio of 1.0 exhibit shear-compression failure, and satisfactory composite action among the castellated steel, precast concrete, and cast-in-place slab is observed during the loading process. Fire duration and the number of fire-exposed surfaces significantly affect the shear capacity, initial stiffness, and ductility of the specimens. When the fire duration increases from 60 min to 120 min, the shear capacity, initial stiffness, and ductility coefficient decrease by 15.8%, 35.8%, and 21.9%, respectively. When the number of fire-exposed surfaces increases from one to three, these parameters decrease by 33.4%, 49.4%, and 30.6%, respectively.关键词：partially encased composite beam (PEC beam);ultra-high performance concrete (UHPC);castellated steel;post-fire;shear behavior2|0|0更新时间：2026-09-09
- 摘要：This paper investigates the elevated temperature mechanical performance of cold-formed steel square hollow sections (SHS). Steady state tests on flat coupons, corner coupons and stub columns were conducted at various temperatures. Mechanical properties of Q355 flat coupons, corner coupons and stub columns at various temperatures were obtained. The influence of the cold-forming effect on the stub column strength was examined. The test results were used to evaluate the applicability of design provisions that account for the cold-forming effect for the cold-formed steel SHS at elevated temperatures. The results indicate that at 400 °C, the yield and ultimate strengths of the corner coupons were 82% and 25% higher than those of the flat coupons, respectively, and stub column strength was 20% higher than the flat coupon yield strength, with the magnitude of enhancement being similar to that at ambient temperature, demonstrating a significant cold-forming effect. This enhancement diminished with increasing temperature. At 600 °C and 800 °C, the mechanical properties of the flat and corner coupons were generally comparable, and the increase in stub column strength over the flat coupon yield strength was 5% and 6%, respectively. The codified design provisions accounting for the cold-forming effect provided conservative predictions for the cold-formed steel SHS stub columns tested at elevated temperatures, with GB/T 50018 and EN 1993-1-3 provisions yielding results close to experimental values, while the AISI S100 provisions were relatively more conservative.关键词：cold-formed square hollow section;elevated temperature test;mechanical properties;cold-forming effect;stub column;yield strength7|1|0更新时间：2026-09-01
- 摘要：The composition of residential plant communities is influenced by multiple categories of factors, including socioeconomic and built environment characteristics. However, existing studies have predominantly focused on the effects of single categories of factors, and there remains a lack of understanding regarding how these multiple categories of factors interact to influence residential plant communities. This study investigated 106 residential communities in the central area of Chongqing. A comprehensive survey was conducted to document their family and genus composition, life forms, biogeographic origin, and ornamental characteristics. In parallel, three socioeconomic indicators (population density, property management fee, and housing price) and four built-environment indicators (parcel area, building age, floor-area ratio, and green-space ratio) were collected for each community. Univariate regression analysis were employed to examine the relationships between socioeconomic and built-environment factors and characteristics of residential plant communities, including species richness, number of individuals, proportion of native species, proportion of deciduous species, proportion of ornamental species and proportion of arbor species. Results indicated that only species richness is significantly influenced by socio-economic factors, built environment factors, and their interactions. Species richness was positively associated with housing prices and property management fees, but negatively associated with building age. Significant interaction effects were identified between housing price and land area, as well as between population density and building age. Specifically, larger land area weakened the positive effect of housing price on species richness. High building age and high population density synergistically suppress species richness.关键词：residential green space;plant community characteristics;socioeconomic characteristics;built environmental characteristics;interaction effects6|1|0更新时间：2026-08-25
- 摘要：Soil-structure interfaces govern stress transfer and deformation compatibility in pile-supported systems. However, the original Lashkari thin-layer interface model was mainly developed for monotonic loading and has limited capability to describe loading reversal, cyclic softening, and accumulated volumetric deformation. In this study, the Lashkari model is extended within the critical-state and bounding-surface plasticity framework. A loading-direction-dependent dilatancy relation is introduced to distinguish the plastic flow directions during loading, unloading, and reloading. The plastic modulus formulation is also modified by incorporating the stress ratio at the most recent load reversal, enabling the model to account for loading-history dependence. The model is validated against monotonic direct shear tests on Hostun and Toyoura sand–structure interfaces under different normal boundary conditions. The predicted shear stress and normal displacement responses agree reasonably well with the experimental results. The model is then used to predict interface responses under cyclic loading. The results indicate progressive degradation of peak shear stress and accumulation of contractive deformation with increasing cycle number. Within an individual cycle, contraction-to-dilatancy transition may occur during loading, whereas unloading is predominantly contractive. Under constant normal stiffness conditions, accumulated normal displacement causes a reduction in normal stress and accelerates shear stress degradation. The proposed model provides a unified framework for describing strain hardening, strain softening, and dilatancy evolution of sand–structure interfaces. Nevertheless, its cyclic performance requires further quantitative validation using independent cyclic shear tests.关键词：soil-structure interface;constitutive model;bounding surface theory;critical state theory;cyclic loading;dilatancy evolution5|0|0更新时间：2026-08-21
- 摘要：To elucidate the degradation of bond-slip behavior at the interface between high-strength engineered cementitious composite (HS-ECC) and steel bars after exposure to elevated temperatures, central pullout tests were conducted on 24 HS-ECC-steel bar specimens. The specimens were divided into six groups: unheated and exposed to 200, 300, 400, 600, and 800 °C. Specimens were heated at 5 °C/min to the target temperature, held for 30 min, and then naturally cooled to room temperature in the furnace. Central pullout tests were performed under displacement-controlled loading. Combined with post-fire compressive and direct tensile tests of HS-ECC, the residual mechanical properties, failure modes, bond stress-slip relationships, bond strength, and bond energy were investigated. The results show that the compressive strength of HS-ECC initially increases and then decreases with increasing temperature, reaching 89.4 MPa at 200 °C; however, its strain-hardening behavior is lost after exposure to 200 °C and above. The temperature at the center of the bond interface is markedly lower than that at the specimen surface and exhibits a lagging effect. Specimens exposed to temperatures not exceeding 300 °C mainly exhibit splitting-pullout failure, whereas brittle splitting failure occurs at 400 °C and above. Bond strength first increases and then decreases with increasing central temperature of the bond interface, reaching 26.23 MPa at approximately 97 °C, 9.2% higher than that of unheated specimens, and decreasing to 9.93 MPa at 575 °C. Bond energy decreases rapidly with increasing temperature and is more sensitive than bond strength in reflecting the deterioration of interfacial bond toughness. Overall, HS-ECC retains splitting-pullout composite failure after exposure to temperatures not exceeding 300 °C, and fiber bridging contributes to maintaining the interfacial bond toughness.关键词：engineered cementitious composites (ECC);reinforced concrete structure;elevated temperature;pullout test;bond-slip5|0|0更新时间：2026-08-20
- 摘要：The widespread application of neutralization processes in acid mine drainage (AMD) remediation engineering has established Ca2+ as a key intervention ion in the secondary mineral precipitation system. This study employed a chemical synthesis method to synthesize calcium-doped schwertmannite (Ca-Sch) and investigated the effects of Ca2+ on the removal of Cr(Ⅵ) by schwertmannite, as well as the differences in the speciation distribution of chromium on the mineral surface. Additionally, toxicity leaching experiments were conducted to explore the release behavior of Cr(Ⅵ) under different pH conditions. Results showed that when the initial concentration of Cr(Ⅵ) was 10-50 mg/L, the adsorption capacity of Ca-doped schwertmannite for Cr(Ⅵ) increased from 6.27-22.4 mg/g to 6.15-24.3 mg/g. The adsorbed Cr(Ⅵ) in Ca-Sch mainly existed as amorphous mineral-bound form (F3) and mineral-bound form (F4). The addition of Ca2+ could increase the stability of Cr(Ⅵ) immobilized in schwertmannite under certain conditions. Results of toxicity leaching test indicated that the release of Cr(Ⅵ) increased with the rising pH. For Ca-Sch samples, the cumulative release amounts of Cr(Ⅵ) after 30 days at pH values of 2, 4, and 6 achieved to be 0.63 mg/g, 4.11 mg/g, and 8.04 mg/g, respectively with an initial Cr(Ⅵ) concentration of 50 mg/L. XRD results confirmed that the characteristic peaks of goethite occurred in Ca-Sch samples after toxicity leaching tests were weaker than those in pure schwertmannite. The findings of this study suggested that the introduction of Ca2+ slightly enhanced the crystallinity of schwertmannite after formation, thereby improving the environmental stability of schwertmannite and reducing its potential environmental risks during environmental remediation and treatment.关键词：schwertmannite;environmental stability;calcium;release;hexavalent chromium5|0|0更新时间：2026-08-20
-
- 摘要：In this paper, finite element analysis is employed to systematically investigate the temperature fields of reinforced concrete columns during both the heating phase and the entire heating–cooling process of fire exposure, and to calculate the compressive bearing capacity of columns under fire and after fire. The influences of key parameters, including the number of fire-exposed surfaces, cross-sectional dimensions, heating duration, fire scenarios (ISO 834 standard fire and non-standard fires), material strength, longitudinal reinforcement ratio, and eccentricity ratio, on the compressive bearing capacity are examined. By incorporating the 500 ℃ isotherm reduced cross-section method, a simplified calculation method for the bearing capacity of columns under fire and after fire is proposed. The results indicate that the longer the heating duration and the fewer the fire-exposed surfaces, the greater the time lag between the end of heating and the moment when the column reaches its maximum thermal damage during the cooling phase. Additionally, longer heating duration, more fire-exposed surfaces, and smaller cross-sectional dimensions lead to more significant additional concrete damage induced by the cooling phase. After a 2-hour standard fire exposure, the post-fire axial compressive bearing capacity of the 13 groups of columns decreases by approximately 4% to 8% compared with that under fire, and this reduction is smaller than the reduction in the area within the 500 ℃ isotherm, which ranges from 10% to 30%. Based on the proposed prediction formulas for the proportion of the area within the 500 ℃ isotherm and for reinforcement temperature under both standard fire and post-fire conditions, together with the 500 ℃ isotherm reduced cross-section method, the axial and eccentric compressive bearing capacities of columns under and after standard fire can be predicted with good accuracy, although the prediction errors for eccentric loading cases tend to increase with prolonged heating duration. Combined with the (modified) equal-energy method, the proposed simplified method can be extended to non-standard fire scenarios, providing a practical reference for the rapid bearing capacity assessment of columns in real-world engineering applications.关键词：reinforced concrete column;under fire;after fire;load-bearing capacity;simplified calculation method4|0|0更新时间：2026-08-18
-
- 摘要：This study focuses on Q890D high-strength steel. A three-stage experimental program, including pre-damage, high-temperature exposure, and tensile testing, was conducted to systematically investigate the evolution of residual mechanical properties under the coupled effects of different pre-tensile strain amplitudes and peak temperatures. Four pre-tensile strain amplitudes, i.e., 0, 0.7%, 2.5%, and 5.0%, and seven peak temperatures, i.e., 25, 150, 300, 450, 525, 600, and 750 ℃, were considered. The residual stress–strain curves and key parameters, including elastic modulus, yield strength, ultimate strength, and fracture strain, were obtained under different conditions. The results show that, for specimens without pre-damage, stiffness and ductility changed slightly in the temperature range of 25~600 ℃, whereas the residual strength exhibited a non-monotonic trend of first decreasing and then increasing. The influence of pre-damage on elastic modulus was not significant in the low- and medium-temperature range, but became pronounced at 750 ℃. At temperatures of 600 ℃ and below, pre-damage could mitigate the reduction in strength but significantly deteriorated ductility, and the effect intensified with increasing damage level. When the temperature rose to 750 ℃, both strength and deformation capacity recovered to some extent, indicating a pronounced coupled effect. Based on the test results, a bivariate polynomial was adopted to fit the reduction factors of the mechanical parameters, and a modified constitutive model was proposed on the basis of the Poh constitutive model by incorporating the effect of pre-damage. The proposed model is applicable to the residual mechanical response of Q890D high-strength steel in post-earthquake fire scenarios.关键词：Q890D high-strength steel;pre-damage;post-fire;mechanical properties;constitutive model4|0|0更新时间：2026-08-15
-
Experimental study on high-temperature performance of coal gangue lightweight aggregate concrete AI导读
摘要：To promote the resource utilization of coal gangue as solid waste and to investigate its fire resistance in building structures, an experimental study was conducted on the thermal and mechanical properties of coal gangue lightweight aggregate concrete (CG-LWAC) at elevated temperatures, leveraging its advantages of lightweight and superior thermal insulation. Standard CG-LWAC specimens were prepared and subjected to various target temperatures ranging from ambient temperature to 1 000 ℃ using a high-temperature electric furnace. The mass loss, thermal conductivity, and complete stress-strain curves under uniaxial compression were systematically measured. Furthermore, the evolution of key parameters, including peak stress, peak strain, and elastic modulus with respect to temperature, were comprehensively analyzed. The results indicate that as the temperature increases, the mass loss of CG-LWAC continuously increases due to the evaporation of internal moisture and the decomposition of hydration products. Due to the inherent porosity of the aggregates and the increased porosity caused by the thermal deterioration of the cement matrix,, the thermal conductivity exhibits a significant non-linear decline as temperature increases. Regarding mechanical properties, both peak stress and elastic modulus undergo severe degradation with increasing temperature, with the rate of deterioration accelerating significantly beyond 400°C. Conversely, the peak strain increases substantially, reflecting enhanced ductility and structural loosening, which manifests as a progressive flattening of the stress-strain response.关键词：coal gangue;lightweight aggregate concrete;thermal parameters;high-temperature performance;failure modes;mechanical indicators2|0|0更新时间：2026-08-12 - 摘要：To investigate the influence of slabs on the post‑earthquake fire performance of beam‑column joints, pre‑seismic damage was imposed through low‑cycle reversed loading at the column ends. The damage evolution, internal force distribution, temperature response, and post‑earthquake fire resistance of composite beam joints and bare steel beam joints were compared and analyzed, and various parametric analyses were conducted. The results indicate that: the concrete slab can significantly enhance the overall stiffness and load‑carrying capacity of the joint, optimize the internal force transfer in the column, and avoid stress concentration; the slab possesses excellent thermal insulation performance, which can effectively delay the temperature rise of steel beams and alleviate the degradation of material properties at elevated temperatures; the fire resistance of composite beam joints is obviously superior to that of bare steel beam joints, and the slab can increase the average fire resistance rating of the joint by approximately 18.43%; as the beam load ratio increases, the proportion of bending moment shared by the slab through cooperative flexural action increases continuously, and the stress in the steel beam is stabilized through internal force redistribution, effectively restraining the development of beam‑end deformation and rotation. Parametric analysis shows that slab thickness serves as a critical parameter affecting the post-seismic fire resistance of joints. The concrete slab improves the joint fire performance through the coupling effect of mechanical coordination and thermal insulation protection.关键词：concrete-filled steel tubular (CFST) joint;seismic damage;fire resistance;concrete slab;finite element analysis4|0|0更新时间：2026-08-12
- 摘要：To evaluate the damage degree of granite after fire exposure, this study conducted uniaxial compression tests, Brazilian splitting tests, X-ray computed tomography (CT) scanning, X-ray diffraction (XRD) analysis, and colorimetric analysis. These tests aimed to investigate the changes in color, mesostructure, physical properties, and mechanical properties of granite subjected to high temperatures, and to explore the correlations among these alterations. The results indicate that as the temperature increases, internal microcracks gradually interconnect to form a complex network, and both the fracture volume ratio and the fractal dimension of cracks increase, leading to a decrease in mechanical strength and ultrasonic velocity. Particularly in the temperature range of 450 ℃ to 600 ℃, all physical and mechanical indicators experience abrupt changes due to the thermal stress induced by the α-β phase transition of quartz. At 150 ℃, however, the tensile strength exhibits a temporary rebound due to a thermal hardening effect. After high-temperature exposure, the attenuation amplitude of ultrasonic velocity is greater than that of mechanical strength, specifically following the pattern of "ultrasonic velocity attenuation > tensile strength attenuation > compressive strength attenuation". The luminance of the granite generally increases with the rising exposure temperature. Notably, at 300 ℃, the granite exhibits a yellowish-brown appearance due to the oxidation of ferrous iron and the thermal decomposition of clinochlore. The results of colorimetric analysis can serve as an effective auxiliary indicator for estimating the exposure temperature of granite. Furthermore, the comprehensive evolutionary patterns of multi-dimensional indicators provide a quantitative basis for the post-fire damage assessment of stone structures.关键词：granite;fire-induced high temperature;mechanical properties;fractal dimension;mesostructure;damage3|0|0更新时间：2026-08-11
-
Experimental study and analysis of flexural cracking performance of UHPC stay-in-place formwork AI导读
摘要：With the development of prefabricated buildings, higher requirements have been imposed on the self-supporting performance of formwork during construction. However, conventional concrete formwork suffers from large self-weight, cracking susceptibility, and limited spanning capacity, making it difficult to satisfy the demand for lightweight and high-strength construction. In this study, six UHPC stay-in-place formwork specimens with a span of 1.8m and a thickness of 40 mm were designed, and flexural cracking tests under uniformly distributed loading were conducted with steel truss reinforcement as the main parameter. The load-strain development and load-deflection curves were analyzed. The results show that the cracking loads of plain UHPC slabs and truss-reinforced UHPC slabs were 6.53 kN/m2 and 7.39 kN/m2, respectively, indicating that the steel truss reinforcement can effectively improve the cracking resistance of UHPC slabs. Considering the tensile plasticity and sectional characteristics of UHPC, the plastic influence coefficient of section modulus, - 摘要：Cold-formed thin-walled steel (CFS) members, due to their large cross-sectional shape coefficient and extremely thin wall thickness, heat up rapidly under fire conditions, making them highly susceptible to performance degradation and instability failure. Their fire resistance design and theoretical evaluation face significant challenges. To explore the fire resistance performance and fire resistance design methods of cold-formed thin-walled steel members, the latest research progress in fire resistance testing, finite element numerical simulation, and theoretical calculations for components such as cold-formed thin-walled steel walls, build-up section members, steel plate shear walls, and floor slabs was summarized. The study revealed that non-uniform thermal-mechanical coupling effects and the high-temperature cracking and spalling of fireproof protection materials are key factors controlling the mechanical performance evolution and structural failure of members under fire. However, the influence of residual stress, cold bending effects, and other factors on fire resistance performance has been insufficiently considered, and research on multi-hazard coupled failure mechanisms and simplified calculation methods for engineering applications requires further improvement. The fire resistance design methods for cold-formed thin-walled steel members in Chinese, European, American, and Australian codes were summarized and compared through case study analysis, revealing certain differences in parameter selection and verification requirements among the codes. The calculated results exhibited significant dispersion and failed to adequately account for the coupling effects of non-uniform fire exposure. Finally, future research trends were outlined.关键词：cold-formed steel;fire performance;non-uniform temperature field;code comparison;thermo-mechanical coupling mechanism8|0|0更新时间：2026-08-11
- 摘要：Concrete-encased concrete-filled steel tubular (CECFST) members have been widely used in engineering structures owing to their high bearing capacity, favorable fire resistance, and good corrosion resistance. The lateral impact finite element model was developed in ABAQUS to investigate the impact resistance of CECFST members after exposure to fire. After validating the reliability of the model, the post-fire impact-resisting mechanism of CECFST members was analyzed. The effects of fire exposure duration, axial load ratio, impact velocity, impact mass, and material strength on impact performance were further examined, and corresponding design recommendations were proposed. The results indicate that CECFST members after exposure to fire mainly exhibit combined flexural-shear failure under lateral impact, and the plastic deformation of the outer reinforced concrete component serves as the primary energy dissipation mechanism. The impact resistance of the members decreases significantly with increasing fire exposure duration. Compared with the unheated member, the plateau impact force decreases by 28.8%, and the maximum mid-span deflection increases by 58.0% after 60 min of fire exposure. When the axial load ratio increases to 0.8, the member undergoes instability failure under impact loading. Increasing the yield strength of the steel tube and the strength of the outer concrete can improve the impact resistance of the member, whereas the strengths of the longitudinal reinforcement and core concrete have relatively limited influence on the post-fire impact performance.关键词：concrete-encased concrete-filled steel tubular (CECFST) members;post-fire;impact resistance;finite element analysis;mechanism analysis3|0|0更新时间：2026-08-11
- 摘要：To investigate the seismic performance of composite high-strength spiral stirrup-confined honeycomb steel reinforced concrete (CHS-HSRC) short columns after exposure to high temperatures, four short column specimens with different configurations were designed and tested under quasi-static loading. The experimental variables included the stirrup configuration (traditional stirrups, rectangular crossed spiral stirrups, and inner-circular and outer-square spiral stirrups) and the thermal exposure condition (ambient temperature and post-high temperature). The effects of the transverse confinement mechanism and high-temperature deterioration indicators on the failure modes, hysteretic behaviors, skeleton curves, bearing capacity, ductility, and energy dissipation capacity of the specimens were systematically explored, and a restoring force model was established. The test results indicate that the macroscopic failure of all composite short columns is dominated by shear failure. In contrast, the novel inner-circular and outer-square spiral stirrup system can construct a continuous and dense spatial confinement effect, effectively restraining the collapse of the damaged core concrete, and steadily increasing the ultimate failure drift ratio from 1/40 to 1/30. The quantitative analysis shows that the average ductility coefficient of the inner-circular and outer-square spiral stirrup specimens after high temperatures reaches 2.42, which is a substantial increase of 37.5% compared to the traditional stirrup specimens under the same conditions. Furthermore, the cumulative energy dissipation at the late loading stage increases by 41.82%, significantly alleviating the pinching effect of the hysteretic curves and the rapid stiffness degradation caused by high temperatures. The study demonstrates that after suffering high-temperature damage, the combined system of inner-circular and outer-square spiral stirrups and honeycomb steel can exhibit outstanding damage tolerance and engineering application resilience under multi-hazard coupling.关键词：composite high-strength spiral stirrup;honeycomb steel reinforced concrete;concrete short columns;high temperature;stirrup configuration;restoring force model3|0|0更新时间：2026-08-10
- 摘要：To improve the efficiency of tower construction and the quality of tower assembly, a new type of butted cross member structure is proposed. The structure interrupts the traditional continuous angle steel and uses T-shaped butt plates to form butt joints. Firstly, two specifications of cross members were designed and tested to reveal their failure modes and load transfer mechanisms. Secondly, finite element models were established to compare the performance differences between the new butted cross member and the traditional continuous cross member, and to analyze the influence of stress ratio, cross member specification, and main member slope on the bearing capacity. Finally, the applicability of current design code methods to the new butted cross member was discussed. The results show that the main failure modes of the butted cross member are in-plane instability of the compression member or shear failure of the tension member hole wall. During loading, the out-of-plane deformation of the compression member exhibits an S-shaped curve, and the overall rotation of the structure leads to internal force redistribution. Compared with the traditional continuous cross member, the bearing capacity and stiffness of the butted cross member on the compression side are basically equivalent, but the stiffness on the tension side is reduced. The bearing capacity of the butted cross member increases with the increase of stress ratio, cross member specification, and main member slope, and the influence of leg thickness, leg width, stress ratio, and main member slope decreases in that order. The calculated values according to the current GB 50017-2017 code have a large safety margin and are applicable to the design of butted cross members with sufficient tension member restraint.关键词：cross member;butted joint;bearing capacity;calculation method;stress ratio3|0|0更新时间：2026-08-10
- Address：Journals Department, Chongqing University, 174 Shazhengjie, Chongqing 400044, P.R.China Postal code：400044
- Tel：+86-23-65111322 Email：xuebao@cqu.edu.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0