This paper introduces the U.S. standard system for existing buildings， analyzes the seismic evaluation techniques， and focuses on the FEMA P-154-2015 rapid visual screening method and the ASCE/SEI 41-23 three-level evaluation process. The United States adopts a grading mode characterized by “graded screening， differentiated evaluation， and targeted reinforcement” for the governance of existing buildings. This mode offers the advantages of flexibility and high efficiency， while also having certain limitations. By comparing the standards of the two countries and considering China's actual conditions， this paper proposes recommendations， such as defining benchmark buildings to simplify the evaluation process and improving performance-based assessment methods to complement traditional appraisals. It aims to provide technical references for construction projects under “the Belt and Road” initiative， thereby offering insights for the scientific and standardized management of existing buildings as well as for urban renewal.

The To elucidate the propagation laws of vibrations generated during the operation of variable-frequency equipment and the influence of such vibrations on building structures， an engineering project incorporating such equipment was investigated through field vibration measurements. Vibration response data were collected at the equipment source， along multiple propagation paths， and on different floors of the building， enabling an examination of the effects of excitation frequency， propagation distance， and spatial direction. The results indicated that the vibration propagation in soil exhibited obvious frequency-dependent characteristics， with the vertical acceleration transmissibility decreasing as the operating frequency increased. Notably， the vibration propagation showed significant directional anisotropy， with the horizontal transmissibility 30% to 50% higher than the vertical one. Vibration amplitude decayed approximately exponentially as the propagation distance increased. Based on the measured data， a quantitative relationship between vertical acceleration transmissibility and propagation distance considering excitation frequency was established. The relationship revealed that vibrations attenuated to the ambient background level at a distance of approximately 200 to 220 m from the vibration source. The vibration distribution inside the building was jointly governed by floor height and structural configuration， and distinct floor vibration response characteristics in different directions were observed due to differences in structural stiffness.

Local deformation is a common damage to steel structures， and 3D reconstruction is an important approach to evaluate the bearing capacity of locally deformed angle steels. To accurately evaluate the accuracy of the SfM （Structure from Motion）-MVS （Multi-View Stereo） 3D reconstruction algorithm in establishing point cloud models of locally deformed steel components， this study proposed an accuracy evaluation method for angle steel point cloud models based on spatial Euclidean distance. Four types of locally deformed angle steels with two thicknesses were selected as the research objects， and an accuracy verification test was carried out on the digital image models of locally deformed steel components. The iterative closest point algorithm was used to align the test point cloud with the reference point cloud in space， and the accuracy of the point cloud model was quantified according to the Euclidean distance between corresponding points， so as to verify the accuracy of the angle steel point cloud model from a 3D perspective. The results showed that through the accuracy evaluation of the angle steel point cloud model， in the height and width directions， the points within the allowable range of dimensional deviation in the 3D point cloud models of the four types of locally deformed angle steels accounted for approximately 98% of the total number of point clouds in the models； in the thickness direction， the average error of the 5-mm-thick angle steel point cloud model was approximately 1.09 mm， while the average error of the 10-mm-thick angle steel point cloud model was approximately 1.02 mm； in the local deformation area， the average error of the four angle steel point cloud models was approximately 1.00 mm.

To address the problem of missing multi-source monitoring data of offshore wind turbines caused by sensor failures or communication interruptions under harsh operating conditions， this paper proposes a novel imputation model based on a multi-head gated residual network. This method achieves collaborative fusion of supervisory control and data acquisition （SCADA） data and structural vibration monitoring data through feature concatenation， employs a gated residual network to extract deep nonlinear coupling features， and uses a multi-head parallel output architecture for the independent reconstruction of these two heterogeneous data types. During the training stage， a dynamic masking mechanism combined with a hybrid loss function is adopted to enhance the model’s adaptability to complex aerodynamic operating conditions. Validated with field data from a 10 MW offshore wind turbine， the proposed model achieved a high coefficient of determination under training conditions， enabling accurate reconstruction of missing multi-source data. In generalization tests for non-training periods， although the coefficient of determination of the model’s predictions fluctuated slightly， the model still effectively captured the overall trends of monitoring signals. Notably， the degradation in generalization performance for vibration data was less pronounced than that for SCADA data， demonstrating its greater stability. The proposed method can significantly improve the completeness and reliability of multi-source monitoring data for wind turbines and holds considerable potential for engineering applications.

Hyperbolic cooling tower shells are mostly cast-in-place reinforced concrete thin-walled structures. Their high-altitude construction poses significant challenges， and geometric imperfections often occur due to issues in construction layout accuracy. Focusing on a specific engineering case， this study employed terrestrial laser scanning （TLS） technology to capture precise geometric imperfection data of the tower shell. Based on the scanned data， finite element models of the hyperbolic cooling tower， both with and without geometric imperfections， were developed using ABAQUS. The effects of geometric imperfections on the mechanical properties of the cooling tower， as well as the sensitivity of different load effects to these imperfections， were systematically investigated. The results indicated that when the actual imperfection magnitude was introduced based on the measured distribution pattern， the bearing capacity and crack resistance of the tower shell decreased significantly. Moreover， no deterioration in mechanical properties was observed when the imperfection magnitude remained below 150 mm. The effects of dead load and external wind pressure were highly sensitive to geometric imperfections， whereas temperature effects remained almost unaffected. Furthermore， the locations along the meridian lines of the tower shell where the maximum external wind suction occurs were identified as critical regions for safety assessment.

The Shenzhen local standard， Technical Standard for Green Demolition of Buildings， was issued and implemented on January 31， 2025， by the Shenzhen Municipal Standards Committee. Based on this newly compiled standard， the definition， framework， application objectives， and demolition technologies for green demolition were analyzed； the current development status of building demolition methods was summarized and evaluated； and the principles for preparing a special green demolition scheme， which balances the goals of structural dismantling safety and comprehensive utilization of demolition waste， were elaborated. Furthermore， a practical application of the standard was carried out in a building demolition project in the Xinqiao East Area urban renewal project in Shenzhen. The results showed that the technical guidelines established in the standard enabled classified and orderly demolition of existing buildings， leading to classified and graded comprehensive utilization of demolition waste. This achieved an on-site utilization rate of 30% and a comprehensive utilization rate of 100% for the demolition waste， thereby improving the comprehensive utilization level and resource recovery efficiency of the project’s demolition waste. This established a technical paradigm for green demolition of buildings and provided a basis for the promotion and application of green demolition technologies.

The external thermal insulation composite system （ETICS） is crucial for improving building energy efficiency and ensuring building functionality. In recent years， issues such as cracking， hollowing， peeling， and high-altitude falling have occurred frequently， posing a significant threat to public safety. A systematic review was conducted on domestic and international research and engineering practice regarding diagnosis and treatment methods for detection， evaluation， and repair of building ETICS. In terms of detection， non-destructive testing techniques were categorized into four types based on their energy forms and physical mechanisms， namely optical， thermal， electromagnetic， and acoustic. The research progress of various non-destructive testing techniques and commonly used destructive testing techniques was systematically reviewed. A comparative analysis was conducted on the technical points， advantages and disadvantages， and applicable scenarios of various detection techniques. In terms of evaluation， the characteristics and progress of existing evaluation methods were summarized from three aspects： qualitative evaluation， quantitative evaluation， and comprehensive evaluation. In terms of repair， the current development status of existing repair methods was introduced from the perspectives of repair technology， repair materials， and repair strategies. Finally， the deficiencies in the research and engineering practice regarding diagnosis and treatment methods for building ETICS were analyzed， and future research directions were discussed.

Asphalt pavement joints are prone to distresses such as cracking， faulting， and water infiltration. Existing studies mainly focus on material modification and construction techniques， while systematic design of joint components in asphalt layers remains limited. To improve the structural integrity and service performance of pavement joints， this paper proposes a novel joint component with a telescopic double-tube structure and establishes the corresponding construction technology system. First， based on the principle of load transfer and deformation coordination， a telescopic structure with square steel tubes was designed， and its load transfer efficiency under different parameter combinations was analyzed using the finite element method. Second， field monitoring was conducted on an in-service expressway to investigate the strain response of the component under coupled traffic loading and temperature effects. Finally， the construction process and key control measures were summarized. The results showed that the proposed component exhibited excellent load transfer capability and deformation adaptability， with a load transfer coefficient exceeding 0.88 and a low degree of dispersion. Field monitoring results verified its stable mechanical properties， and its strain response was highly consistent with temperature variations and traffic load distribution. The proposed construction method ensured installation accuracy and long-term durability.

This study investigated the fatigue life of steel crane beams through fatigue testing and combined finite element analysis to reveal the stress distribution changes at the support of variable-section beams before and after prestress strengthening. In addition， the equivalent structural stress method was employed to predict the fatigue life corresponding to the initiation of 20 mm cracks at the support. The results indicated that prestress strengthening significantly reduced the stress level at critical welds， while the location of maximum stress and the failure mode remained unchanged. With increasing prestress control values， both the overall failure life of the beam and the crack initiation life at the support were significantly extended. Under a prestress control value of 12.5 t， the strengthening effectiveness factors for overall beam failure and visible support cracks reached 4.08 and 4.23， respectively， demonstrating the effectiveness of high-level prestressing.

The Red Mansion at No. 106 Huangpu Road， Shanghai， was constructed in 1911. It is a three-story brick-wood structure. In its comprehensive protective renovation project， three major challenges were encountered： the simultaneous construction of a complex group of adjacent deep foundation pits， the overall ultra-high jacking by 6.55 m to restore its historical appearance， and the synchronous development of underground space together with the improvement of the building’s seismic performance. To address these challenges， a complete set of key techniques was proposed， integrating underpinning， active deformation control， synchronous high-position jacking， and seismic isolation with story addition. Using an adjustable active underpinning system， the cumulative additional deformation of the Red Mansion during the construction of the surrounding deep foundation pits was controlled within ±5 mm. A relay lifting technique combining "lifting + jacking" was adopted to achieve the ultra-high jacking of 6.55 m， along with the simultaneous high-position rectification of 300 mm. The addition of a seismic isolation layer significantly enhanced the structural seismic performance. After three rounds of whole-process load transfer， the maximum inclination ratio of the building foundation was reduced from the initial 9.12‰ to below 2.5‰， with no new structural cracks generated. This project realized the in-situ preservation， jacking with story addition， and functional upgrading of an outstanding historical building in Shanghai under the condition of simultaneous construction adjacent to a group of deep foundation pits， setting a record for the highest overall jacking height of modern outstanding historical buildings in China.