Haize Pan

Continuous tower crane monitoring enables the recording of changing operating conditions, but interpreting these measurements requires a model of how operational risk states evolve. We combine the Decision-Making Trial and Evaluation Laboratory (DEMATEL), interpretive structural modeling (ISM), and a two-slice dynamic Bayesian network (DBN) for dynamic risk assessment. Six operating indicators define a relative operational risk state from training-referenced percentiles in 60 s time slices. Coverage and activity screening identify eligible observations, while lagged associations and DEMATEL-ISM guide DBN structure screening. The DBN predicts the next-slice state probability and relates each forecast to its inputs through conditional probability contrasts. The case study used one month of records from a tower crane, divided chronologically into training, validation, and test sets. Across 2557 test pairs, the model achieved an area under the receiver operating characteristic curve of 0.6931 and average precision of 0.4571. Its Brier score was 0.1724, compared with 0.1899 for a Markov baseline using only the current risk state. This Brier advantage persisted across eight state definitions, and coupling trend consistently had the largest mean conditional probability contrast. By connecting operating measurements with temporal prediction and factor interpretation, the method supports systematic tracking of changes in tower crane operational risk states.

The compression modulus is a key parameter governing the settlement of bridge foundations. To accurately predict pile-group settlement, this study draws on a high-speed railway bridge project crossing the Haihe Alluvial Plain. Combining field monitoring with theoretical analysis, the compression modulus of clay-bearing strata deeper than 50 m is investigated and state-specific correction factors together with their relation to the liquidity index are proposed. The in-situ compression modulus back-calculated from measured settlement of deep clay is 10.47–22.97 times the laboratory modulus E₀. The correction factor β is closely related to soil consistency: mean β values of 0.585, 0.633, 0.648 and 0.798 are obtained for stiff, firm-to-stiff, plastic and soft clays, respectively. β increases linearly with the liquidity index, showing a strong positive correlation. The sensitivity analysis shows that a deviation of 0.05 in β leads to an error of approximately −17% to +24% in the calculated total settlement, and underestimating β yields unsafe predictions. When the measurement resolution is combined, the overall uncertainty band of β is approximately ±0.06, corresponding to an uncertainty band of approximately −21% to +28% in the calculated total settlement. Recommended values are 0.53–0.65 (stiff), 0.57–0.69 (firm-to-stiff), 0.59–0.71 (plastic) and 0.74–0.86 (soft). Within the 0.5 m disturbed zone below the pile tip, the modulus may be taken as 1.2 E₀ for soft clay, 1.6 E₀ for medium-dense sand and 2.0 E₀ for firm-to-stiff clay. The results provide a parameter basis for the settlement prediction of deep-long pile groups in the Haihe Alluvial Plain.

Tower-crane safety risk is rarely driven by a single defect; it usually emerges from coupled equipment, environmental, operational and management conditions. To make such risk easier to diagnose and control, this study constructed a 45-factor system across nine dimensions: wind load and operating weather, lifting load and operating conditions, surrounding environment, foundation and anchorage, structural connection, mechanisms and key components, electrical control, safety protection and monitoring, and management and emergency capacity. We then developed a two-stage Pearson correlation screening method to reduce redundant indicators without losing dimensional coverage. The first stage combines Pearson correlations with coefficients of variation to remove local redundancy. The second stage uses an information-redundancy contribution index to evaluate the system-level effect of deleting each factor. Based on 178 valid questionnaires, the data showed strong internal consistency and structural suitability (Cronbach’s alpha = 0.961; KMO = 0.898; Bartlett’s p < 0.001). With the final threshold set at p = 0.55, the method retained 16 factors from 45 candidates while preserving all nine dimensions; the retained set remained unchanged when p varied from 0.50 to 0.60. Compared with K-medoids and K-means baselines, the proposed method achieved stronger information explanation and clearer engineering traceability. Fuzzy-set qualitative comparative analysis (fsQCA) further showed that no single condition was necessary for high risk. Six positive truth-table configurations produced three intermediate solution terms (solution consistency = 0.999; solution coverage = 0.490). Across the pathways, adverse weather, lifting demand, surrounding exposure, weak foundation/anchorage and structural-connection weakness repeatedly appeared as core conditions, while mechanism-protection failure and electrical-management failure formed alternative downstream routes. The findings indicate that tower-crane risk develops through coupled pathways rather than isolated factors, and they provide a basis for pathway-oriented inspection and targeted safety control.

Unsafe behavior is a primary cause of construction accidents, with safety attitude being a crucial psychological predictor. While numerous safety attitude and climate instruments exist, many originate from other industries or lack rigorous psychometric validation and contextual adaptation for construction, especially when used to assess construction workers’ safety attitudes. This study developed and validated a multidimensional safety attitude scale (CWSAS) for Chinese construction workers using a three-stage mixed-methods design. Initially, grounded theory interviews with 15 workers and literature analysis generated the item pool. Subsequently, two rounds of Delphi consultation with seven experts refined the scale. Finally, item analysis and exploratory factor analysis were performed on Sample 1 (n = 306), followed by confirmatory factor analysis on an independent Sample 2 (n = 260). The CWSAS comprises 26 items across four dimensions: Safety Cognition, Safety Behavioral Tendency, Safety Emotion, and Organization and Management. This four-factor model, grounded in tripartite attitude theory and reflecting China’s unique safety governance, demonstrated excellent fit, high reliability, and acceptable convergent and discriminant validity. The CWSAS offers a robust tool for assessing and improving construction safety.

Addressing the issues caused by urbanization through urban vitality theory has elicited increasing attention in social environment research. However, few studies focus on vitality itself, such as the generative mechanism of urban vitality (GMUV) and the identification of key factors to vitality improvement. Therefore, a new insight into vitality is presented in this study through the exploration of GMUV based on partial least squares structural equation modeling (PLS-SEM). Concretely, the GMUV and the key factors to vitality improvement are analyzed and identified based on nighttime lights data, points of interest, and the statistical data of the Chengdu-Chongqing Area Twin-City Economic Circle in China. The results show that external representations and internal elements constitute the structural basis of the GMUV and that environmental vitality and social vitality are the key factors to enhance vitality. Finally, suggestions on improving regional vitality are provided to urban policymakers. This study may promote a better understanding of vitality, and the proposed vitality evaluation model may serve as a reference for other regions.