This study proposed a novel framework for quantifying the freeze-thaw resistance of loess, cement-stabilized loess (CSL), and polypropylene fiber-reinforced CSL (PF-CSL) using energy-based indicators derived from electromechanical impedance (EMI) techniques with disk-shaped (DS) sensors. The efficacy of the EMI method was validated by tracking shifts in the primary resonance peak of conductance signatures, which directly correspond to cycle-induced changes in the material's strength (frequency shift) and damping characteristics (amplitude shift). To enhance quantitative assessment, the Root Mean Square Deviation (RMSD) was employed as a robust statistical indicator to characterize the hysteresis observed during each cycle, establishing a strong correlation between the material's cyclic damping capacity and its freeze-thaw resistance. Building on this, two slope indicators (i1 and i2) derived from the cumulative energy dissipation ratios (Sigma ERMSD) were proposed to decouple and quantify distinct energy dissipation mechanisms: initial damage from yielding in early cycles and the steadystate damping that governs durability in later cycles. Experimental results indicate that the 1.0% PF-CSL composite exhibits superior freeze-thaw resistance, evidenced by minimal stiffness variation and the highest damping-driven energy dissipation. Overall, this study validates that the proposed EMI-based energy dissipation indicators provide a quantitative framework for evaluating the multi-cycle freeze-thaw performance of CSL composites.

In response to the ongoing demand for natural aggregates in the construction industry and the urgent need for green utilization of solid wastes, a preparation method for multi-source solid waste-based artificial lightweight aggregates using a silicone mold casting technique is proposed. The artificial lightweight aggregates were composed primarily of coal gangue, slag, fly ash, basalt fibers, a small amount of cement, and water, with quartz sand, waste glass, and a superplasticizer as supplementary components. They were fabricated via a process of mixing, cold-bonding, and subsequent natural water curing, successfully obtaining products with a specified particle shape coefficient.The physical and mechanical properties of the aggregates under seven different mix proportions were systematically evaluated: apparent density 800-900 kg/m3, water absorption around 10 %, and crushing index 9.27 %-15.18 %, along with the compressive strength of the resulting concrete. Experimental results demonstrate that even with 100 % replacement of natural aggregates, the concrete can achieve C30-grade strength, exhibiting high structural integrity and good aggregate-matrix synergy in failure mode. XRD and SEM analyses indicate that the aggregates possess a dense internal structure and complete hydration reactions. LCAbased environmental assessment shows that the production of these aggregates can achieve significant carbon reduction, with optimized groups (G4-G7) even exhibiting net negative carbon emissions, while simultaneously enabling large-scale solid waste utilization and energy savings. This study provides a technically feasible, environmentally friendly, and economically viable solution for valorizing coal gangue and other solid wastes, contributing to the green and low-carbon transformation of the construction materials industry.

Earthen materials are attractive sustainable building solutions due to their low embodied energy and ecological benefits. However, their inherent weaknesses, such as low strength and poor durability, severely restrict modern engineering applications. Traditional physical or chemical modification methods struggle to balance significant improvement in mechanical performance with the preservation of their core sustainable attributes. To overcome this long-standing challenge, this study proposes a paradigm-shifting solution: a prefabricated monolithic lattice–earth composite wall structure. This system abandons the single-material-centered modification approach. Instead, through macroscopic system-level composite design, reinforced concrete lattices and earthen blocks are prefabricated into integral wall panels in a factory. These panels then work collaboratively with the peripheral frame through reliable integral connections. Via quasi-static tests and theoretical analysis on four scaled wall specimens with different design parameters, this study systematically reveals the working mechanism and performance regulation principles of this composite system. The core findings indicate: (1) The system achieves multiple seismic defense lines and a controllable energy dissipation path through a sequential damage mechanism: “earthen material cracking and friction → lattice yielding and energy dissipation → final defense by the frame.” (2) The ratio of the equivalent lateral stiffness of the prefabricated wall panel to the stiffness of the outer frame is a key dimensionless design parameter controlling the failure mode (ductile shear or brittle bending), and the lattice configuration is an effective means to adjust this parameter. (3) Based on tests and an equivalent stiffness model, quantitative design guidelines are proposed, focusing on optimizing lattice density (recommended: 3–4 lattice columns), limiting the aspect ratio (preferably ≤1.5), and ensuring “strong connections.” This study demonstrates that the system, without sacrificing the intrinsic sustainable advantages of earthen materials, successfully endows them with high performance, meeting modern seismic code requirements and potential for prefabricated construction through system integration innovation. It provides a new path with theoretical foundation and practical feasibility to resolve the core contradiction in the modernization of traditional earthen buildings—the incompatibility between ecological attributes and engineering performance. This lays an important foundation for developing next-generation high-performance green building structural systems.

To investigate the interface durability of CFRP-reinforced steel structures under combined salt corrosion and freeze-thaw conditions, this study focuses on a two-layer composite reinforcement system comprising CFRP plates and CFRP fabric. Based on the theory of cohesive force models, a finite element model of the damage evolution at multiple interfaces—steel plate -adhesive layer-CFRP plate-CFRP fabric multi-interface damage evolution in COMSOL Multiphysics. By integrating dilute-medium transport, temperature fields and solid mechanics fields, a fully coupled environmental-mechanical model was established to describe the synergistic evolution of chloride ion ingress and freeze-thaw damage. Numerical simulations reproduced the spatiotemporal evolution of chloride ion concentration fields and pore volume loss in the binder layer under different numbers of freeze-thaw cycles. The results indicate that the two exhibit a positive feedback relationship, whereby damage drives intrusion and intrusion exacerbates damage; environmental synergy is a key factor leading to the accelerated degradation of interfacial bonding performance. In the double-layer reinforcement scheme, the combined load-bearing capacity of the inner panel and outer fabric increased by 16.2% compared with a single-layer panel, and the load-bearing capacity retention rate remained as high as 88.1% after 120 freeze-thaw cycles; Parametric analysis determined that the critical effective bond length for CFRP panels is 200–250 mm, with an optimal adhesive layer thickness of 2.0 mm. This composite reinforcement scheme achieves an optimal balance of load-bearing capacity, ductility and long-term durability through a synergistic mechanism combining rigidity and flexibility with multi-layered protection. It provides theoretical support and design guidelines for the service performance and engineering design of CFRP-reinforced steel structures in salt corrosion–freeze-thaw environments.

To elucidate the influence and underlying mechanisms of double-doped basalt fiber (BF) and aeolian sand (AS) on the mechanical properties and microscopic pore structure of concrete, concrete specimens with varying BF lengths, volume fractions, and AS replacement ratios were prepared. The mechanical properties of the concrete, including compressive, splitting tensile, flexural, and uniaxial compression strengths, were evaluated. In parallel, nuclear magnetic resonance (NMR) was used to characterize the pore structure, while scanning electron microscopy (SEM) provided microstructural insights, enabling a multiscale elucidation of the underlying mechanisms. The results reveal that the strength of basalt fiber aeolian sand concrete (BF-ASC) increases with age, showing rapid development at early ages followed by a gradual deceleration. An exponential function-based model accurately captures the early-age strength development. Compressive, splitting tensile, and flexural strengths, as well as uniaxial compressive peak stress and elastic modulus, exhibit a non-monotonic behavior, initially increasing and then decreasing with increasing BF length, BF volume fraction, and AS replacement ratio. In addition, the failure mode of concrete changes from brittle to ductile with fiber incorporation. The toughness index exhibits a trend of first increasing and then decreasing with increasing BF length and AS replacement ratio. Notably, it increases progressively with BF volume fraction, reaching an increase of 90.96% at a volume fraction of 0.3% compared with the reference group. The BF-ASC constitutive model, constructed by describing the stress–strain relationship piecewise, provides a more accurate representation of its deformation and failure characteristics. NMR analysis indicated that appropriate incorporation of BF and AS effectively optimized the pore structure and enhanced the compactness of BF-ASC, whereas excessive incorporation led to pore-structure deterioration. Under the optimal BF condition, the harmless pore fraction increased from 62.51 to 68.41%, while the multiple harmful pore fraction decreased from 16.42 to 12.72%. Furthermore, the pore structure was further optimized when the aeolian sand replacement ratio was 25%. SEM observations revealed fiber pull-out, breakage, and effective fiber-matrix bonding. In the double-doped system, BF and AS interact synergistically within the concrete matrix, modifying both the microstructure and macroscopic mechanical properties of the material. When incorporated at appropriate dosages, BF effectively suppresses microcrack initiation and propagation through its bridging effect, while AS enhances matrix compactness and fiber-matrix interfacial bonding through its filling effect. This synergistic interaction significantly improves both the mechanical properties and pore structure of concrete. Based on the parameter range investigated in this study, the optimal combination is a BF length of 18 mm, a volume fraction of 0.1%, and an AS replacement ratio of 25%.

To address the synergistic challenges of construction efficiency and seismic performance in traditional prefabricated shear wall structures, this study proposes a composite coal gangue concrete prefabricated grid wall system. Low-cycle reversed loading tests were conducted on three half-scale coal gangue grid wall specimens to systematically investigate the effects of grid configurations on failure mechanisms and seismic performance. Experimental results demonstrated that all specimens exhibited flexural-shear failure modes with symmetric hysteretic and skeleton curves. The failure sequences of specimens GGSW-2 and GGSW-4 followed a multi-defense-line seismic mechanism, progressing from non-reinforced concrete zones to confined grid elements and finally to edge-constrained components. Among them, GGSW-2 achieved the highest load-bearing capacity, optimal ductility, and superior energy dissipation performance. While GGSW-4 exhibited reduced load-bearing capacity, its lightweight characteristics and thermal insulation advantages make it suitable for low- to mid-rise buildings. In contrast, GGSW-5 experienced brittle failure due to stress concentration at the base joint, necessitating optimization of vertical joint details to enhance ductility. The tests revealed the constraint effect of the grid system on crack propagation, validating the functional zoning design philosophy of the prefabricated coal gangue grid wall system. This study provides theoretical insights for improving seismic performance and functional differentiation in prefabricated structures.

This study proposes a novel multi-task graph neural network (MT-GNN) surrogate model for efficient, multiobjective cable force optimization in cable-stayed bridges. The MT-GNN is trained on heterogeneous graph data derived from finite element simulations conducted over a Latin Hypercube Sampled design space, leveraging a Huber loss function with uncertainty weighting to concurrently predict node displacements and element bending moments. Integrating this trained MT-GNN into the NSGA-II framework enables rapid optimization aimed at simultaneously minimizing total girder vertical displacements and total bridge bending moment energy. Case studies on two-dimensional (2D) and three-dimensional (3D) single-pylon cable-stayed bridges demonstrate that the proposed framework achieves prediction accuracies comparable to finite element (FE) analysis, while drastically reducing computational costs. The optimized designs exhibit superior structural performance over traditional strategies, particularly for complex 3D configurations. These results demonstrate that the MT-GNN-based framework offers a computationally efficient, robust, and practical tool for multiobjective cable force optimization in cable-stayed bridges.

Since structural damage commonly manifests as a local phenomenon, structural health monitoring (SHM) of critical local areas is significant. However, traditional output-only time series models have certain limitations in diagnosing local damage. Although these models are sensitive to the local diagnosis of structural nonlinear damage, they often fail to provide valid information on local damage when dealing with damage induced by linear stiffness reduction. This paper proposes an unsupervised local damage diagnosis method based on the substructure isolation technique and time series models. Valid information on local damage to the structure is extracted by isolating the substructure of interest and calculating the pseudo-free response (PFR). The autoregressive (AR) model is then employed to extract features from the PFR, and the AR spectrum is used as damage-sensitive features (DSFs). Furthermore, a statistical decision-making approach combining log-spectral distance with a nearest-neighbor rule is proposed to mitigate the influence of uncertainties in numerical calculations of PFR on damage diagnosis results. Finally, the effectiveness of the proposed method is validated using a numerically simulated four-story plate-column structure and a three-story test bed structure from Los Alamos National Laboratory.

To understand the influence of different curing conditions on the interface bonding performance of CFRPreinforced steel plates, tensile tests were conducted on epoxy resin dog bone specimens and CFRP-reinforced steel plate double lap specimens. The study explored the tensile performance of dog bone specimens under different curing temperature/time conditions and the mechanical properties of double lap specimens under different curing pressures and curing temperature/time conditions. The results indicate that increasing the curing temperature can shorten the curing time of dog bone specimens and also improve their elastic modulus and tensile strength. Elevating the curing pressure, curing temperature, and extending the curing time cause a transition in the failure mode of the double lap specimens from surface fiber stripping of the CFRP plate to a mixed failure dominated by surface fiber stripping and adhesive-steel interface debonding, and the bearing capacity, interface ultimate slip, and peak shear stress of the specimens significantly increase, with the shear stress concentration zone gradually expanding from the loading end towards the free end, simultaneously, the ductility of the specimen increased, and the failure process was delayed. The ultimate load, interface peak shear stress, and ultimate slip of the specimens cured at 90 degrees C are significantly higher compared to the control group cured at 20 degrees C and 0.01 MPa. However, with increasing curing time, the rate of growth shows a decreasing trend.

This article investigated the feasibility of electromechanical impedance (EMI) techniques, employing a developed disk-shaped (DS) piezoelectric sensor, for strength monitoring of cement-stabilized loess (CSL), a base material for pavement foundations. Through a series of experiments, the DS sensor was tested on CSL specimens under varying moisture conditions and applied loads. The results demonstrated that the DS sensor could precisely identify the optimal initial moisture content for achieving the maximum dry density in CSL, closely aligning with the conventional Proctor tests. Moreover, the EMI techniques were proven capable of monitoring the strength development of CSL during hydration. They also showed high sensitivity to changes in post-hydration moisture content, thus validating their feasibility for strength monitoring of CSL. However, the sensors exhibited limited sensitivity to applied loads on hardened CSL specimens. The findings demonstrated the potential of EMI techniques, facilitated by DS sensors, as a promising approach for the strength monitoring of CSL in fields.

The objective of this study is to investigate the dynamic compressive mechanical properties of concrete under the combined effects of freeze-thaw (F-T) and salt erosion. The Split Hopkinson Pressure Bar (SHPB) test system was employed to conduct dynamic compression tests on concrete specimens subjected to 0 similar to 250 cycles of F-T in NaCl solutions with concentrations ranging from 0 % to 8 %. The influence of strain rate, F-T cycles, and chloride concentration on the dynamic properties of concrete were analyzed, and a constitutive model considering rate-dependency was developed to describe its compressive mechanical response. The research findings suggest that the dynamic compressive strength of concrete gradually increases with an increase in strain rate, indicating a strengthening effect due to higher strain rates. Additionally, the dynamic growth factor exhibits an exponential relationship with the logarithm of strain rate. Moreover, an increase in the number of F-T cycles results in a gradual reduction in the dynamic compressive strength of concrete and an accompanying increase in specimen fracture. Furthermore, the dynamic compressive strength of concrete exhibits a non-linear trend concerning chloride solution concentration: initially decreasing and subsequently increasing. The minimum compressive strength is observed at a concentration of 3.5 %, indicating the most severe damage to the concrete. However, it should be noted that a higher strain rate mitigates the influence of chloride solution concentration on specimen breakage. To comprehensively understand the mechanical behavior of concrete under combined F-T and salt erosion effects, we propose a dynamic constitutive model based on established mechanical and damage theories relevant to composite materials. The experimental results demonstrate that the proposed model effectively captures the mechanical response of concrete subjected to the combined influence of F-T and salt erosion.

Torsional stiffnesses of chords contribute considerably to the sectional torsional stiffness of steel tubular Vierendeel truss arches and hence determine their out-of-plane buckling. To obtain a more accurate stability design for the Vierendeel truss arches, torsional effects of chords on their out-of-plane stability and failure mechanisms were investigated theoretically and numerically. This paper firstly derives the theoretical formulas of the sectional torsional stiffness and the out-of-plane elastic buckling loads for the pin-ended circular steel tubular Vierendeel truss arches. It is found that incorporating the torsional stiffness of chords can remarkably enhance the sectional torsional stiffness of the Vierendeel truss arches and their out-of-plane elastic buckling loads by ~41%. Then, the out-of-plane elastic buckling loads are calculated for the pin-ended arches by the equilibrium theorem and for the fix-ended arches by the numerical fitting. In both cases, the sectional torsional stiffness and elastic buckling loads are closely dependent on the transverse-to-chord member stiffness ratio (it/ic). Furthermore, the out-of-plane inelastic buckling behaviors are investigated numerically in the end-fixed Vierendeel truss arches with large it/ic, where the ultimate bearing load in full-span radially uniform manner can be significantly enhanced by ~43% by incorporating the torsional stiffness of chords. The calculated reduction factors confirm the design curve b from GB50017-2017 or Eurocode 3 and can provide a conservative design for the out-of-plane stability of the circular steel tubular Vierendeel truss arches.

Sensing performance is crucial for real-world applications of the embedded piezoelectric lead zirconate titanate (PZT) sensors in concrete structures. Based on the electromechanical impedances (EMIs) obtained numerically and experimentally from the embedded PZT sensors, effects of installation orientation and interfacial roughness were investigated on their sensitivity and reliability for quantitative concrete stress monitoring. The numerical results suggest a better sensitivity in the embedded 90° PZT sensors, with planar normal perpendicular to the loading direction, where the conductance amplitude variation is 6.5 times of that of the 0° PZT sensors, with normal parallel to load direction. Further, the improved reliability of the PZT sensors with rough interfaces is observed experimentally, which makes them robust for concrete stress monitoring over a wider sensing range from 0 to 20 MPa. Based on the static analyses, it is noted that the sensing performance of the embedded sensor is significantly affected by the interfacial stiffness degradation induced by the enhanced strain surrounding the sensor. These findings suggest that delaying the interfacial stiffness degradation, i.e., with proper installation orientation and interfacial treatment, could improve the sensing performance of the embedded sensors for quantitative concrete stress monitoring.

Abstract Epoxy resin adhesive (ERA) is an important bond material for carbon fiber reinforced polymer (CFRP) strengthened bridge structures, and its mechanical properties often degrade when used in harsh environments. Fifty-two ERA specimens were prepared and tested to investigate the influences of freeze–thaw (F–T), chlorine dry–wet (D–W), and F–T/D–W on mechanic properties of the ERA. Static tensile tests were conducted after the ERAs were exposed to these environments for 30, 60, 90, and 120 cycles. The experimental results showed that failure of all specimens demonstrated characteristics of brittle failure. Compared with the control group, the tensile strength increased around 40.7, 22.8, and 11.3%, and the elastic modulus increased around 39.2, 34.6, and 38.3% after 120 cycles of the F–T, D–W, and F–T/D–W exposure, respectively. Meanwhile, the stress–strain relationship of the environmental specimens exhibited nonlinear characteristics. However, the stress-strain relationship of the control group without any environmental treatment showed linear. By contrast, the deformation capacity of the environmental specimens was weaker than those of the control group, except for the specimens under the 120 D–W cycles. In addition, variation for the strain energy and tensile strength retention rate of the environmental specimens demonstrated similar trends with the tensile strength, which increased first and then decreased from 30, 60, 90, to 120 cycles. Finally, a strength degradation model of the ERA was proposed to predict the tensile strength under the F–T, D–W, and F–T/D–W exposure.

薄壁空心墩在高墩大跨连续刚构桥中得到了广泛应用,日照作用下超高薄壁空心墩的墩顶偏位对于桥墩施工期和成桥后整体结构线形和受力产生不利影响.该文基于陕西省某特大桥180m高薄壁空心墩,选取施工过程中8月28日至29日和10月11日至12日各24 h的温度场及墩顶位移测试数据,结合有限元分析方法对日 照作用下超高薄壁空心墩温度场及墩顶位移随时间的变化规律进行研究.结果表明:南北墩壁温差受环境温度和昼夜温差影响较大,8月环境气温高,昼夜温差小,南北墩壁温差较小,墩顶偏位较小;10月环境气温低,昼夜温差大,南北墩壁温差较大,墩顶偏位大;墩顶位移与日照壁面温差变化规律一致;墩高达到180 m时,在8℃壁面温差下产生最大52.6 mm的墩顶位移.采用实体有限元法分析得到的墩顶位移和规范计算出的墩顶位移与实测值相比均吻合较好,具有较高的精度.

Bond-type anchorages with plain carbon fiber-reinforced polymer (CFRP) tendon, ribbed CFRP tendon, and CFRP tendon with metallic ribs were fabricated and tested. The contributions of chemical adhesion force, friction force, and bearing force of the surface ribs to the maximum pullout load of a bond-type anchorage with ribbed CFRP tendon were discussed. The influences of the metallic rib type, metallic rib number, and preloading force on the anchoring performance of a bond-type anchorage with CFRP tendon were also investigated. Finite-element simulation was also conducted to help study the working mechanism of wedge plug type ribs. Results show that bilinear and trilinear bond-slip models can characterize the bond performance of a bond-type anchorage with plain and ribbed CFRP tendon, respectively. In addition, bearing forces of surface ribs are limited due to the low shear strength of the CFRP material. However, metallic ribs can address this problem and promote the anchoring performance if the connection between the CFRP tendon and the metallic rib is reliable. A wedge plug type rib exerts a larger contact pressure on the surface of the CFRP tendon during the plugging and loading procedure compared with chip-type rib, making it more reliable than the chip-type rib. Moreover, preloading the wedge plug type rib after plugging eliminates the initial slip between the CFRP tendon and the metallic rib. This allows the wedge plug type rib to function sensitively under pullout load. Consequently, the bond between the CFRP tendon and the grout can work together with the friction between the CFRP tendon and the wedge plug type rib, and thus can avoid the "snap back" phenomenon in the pullout test.

This work proposed a novel approach based on principal component analyses (PCAs) to monitor the very early-age hydration of self-compacting concrete (SCC) with varying replacement ratios of fly ash (FA) to cement at 0%, 15%, 30%, 45%, and 60%, respectively. Based on the conductance signatures obtained from electromechanical impedance (EMI) tests, the effect of the FA content on the very early-age hydration of SCCs was indicated by the predominant resonance shifts, the statistical metrics, and the contribution ratios of principal components, quantitatively. Among the three, the PCA-based approach not only provided robust indices to predict the setting times with physical implications but also captured the liquid-solid transition elongation (1.5 h) during the hydration of SCC specimens with increasing FA replacement ratios from 0% to 45%. The results demonstrated that the PCA-based approach was more accurate and robust for quantitative hydration monitoring than the conventional penetration resistance test and the other two counterpart indices based on EMI tests.

为改善非对称高墩预应力混凝土变截面连续刚构桥成桥后墩顶产生较大偏位带来的不利影响,常在中跨合龙前实施合龙口顶推施工.以安家山河预应力连续刚构桥中跨跨中合龙口施工为研究背景,考虑边、中跨不平衡荷载、收缩徐变、合龙温差等因素确定顶推位移,基于结构力学推导了合龙口顶推力解析式,验证合龙口顶推力解析式的正确性.对比施加非对称顶推力、对称顶推力和未施加顶推力对刚构桥主梁线型、桥墩受力和主梁受力的影响.结果表明:施加对称顶推力比施加非对称顶推力对主梁控制下挠作用更加明显,使得顶推后主梁和桥墩应力水平处于合理的范围内.该研究对大跨度预应力混凝土连续刚构桥合龙施工提供理论与实践依据.

Concrete-filled steel tubular Y-shaped (CFST-Y) piers are good candidates for meeting the structural and aesthetic requirements of bridges. By using the theoretical and nonlinear static (pushover) analyses, the seismic performances of three types of CFST-Y piers were evaluated at different seismic hazard levels. The theoretical formulas were first proposed to estimate the lateral stiffnesses for piers with different pier–deck connections. Then, the structural ductility with the development of plastic hinges in piers was investigated based on the pushover analyses. The results demonstrate that the structural dimensions, deck mass, shear limit, and stiffness of bearings can remarkably affect the formation of hinges and thereby lead to different energy dissipation patterns to achieve the expected performance in piers. The findings suggest an economic design strategy of piers, using CFST-Y members as energy dissipation fuses with multiple hinges, to achieve low-level seismic performance cost-effectively.

混凝土桥塔的裂缝扩展直接影响桥塔的使用寿命,为了探讨温度场对桥塔既有裂缝宽度的影响,以某双塔悬索桥混凝土桥塔为例,对混凝土桥塔的日照温度场、裂缝宽度和深度进行观测,并建立混凝土桥塔实体三维模型,模拟了桥塔的温度场和裂缝的扩展情况.通过实测值与理论计算值比较分析表明,3个季节塔壁内、外表面温度随时间变化近似均呈正弦曲线变化趋势,塔外日较温差比塔内大;桥塔沿壁厚4个方向的温差变化趋势相近,且桥塔内、外表面最大正、负温差均发生在冬季,最大值分别为20.4℃、-11.5℃.桥塔裂缝随着塔壁厚度方向温差变化有明显的闭合和张开现象,最大幅值约为0.14 mm,但裂缝扩展并不明显,可认为裂缝扩展到一定程度后不再发展.然而桥塔裂缝闭合和张开现象造成裂缝修补困难,常规修补方法效果不是很理想,这与实桥裂缝修补后再次开裂的现象十分吻合.