Design Codes Research Articles

Investigation of curve minimum radius in heavy-haul railway to improve wheel wear evolution and wheel-rail contact geometry

To determine the minimum and reasonable radius of horizontal curve for reducing wheel wear in heavy-haul railway design, a HXD locomotive with the wheel arrangement of C0-C0 is taken as the research object. Both the corresponding locomotive dynamic model and wheel wear model are established. Based on the measured wear data in a specific line, the simulation model is verified with the prediction error of wheel wear depth below 0.5 mm in general. The wheel wear evolution rules in 400∼1000m radius curves are studied and compared. The results indicate that, the wheel wear is large and sensitive to curve radius within 400∼600 m. The larger radius curve will be helpful to reduce wheel flange contact and wheel wear. For curve radius increasing from 600m to 1000m, the wheel average wear reduces slowly. Especially for curve radius below around 740 m, the wheel flange wear will be predominant. For radius above 740m, the wheel tread wear becomes the main wear form and the wheel flange wear can be reduced significantly. The increase of curve radius will also improve the wheel-rail equivalent conicity. If the minimum curve radius is set as 800m, the equivalent conicity difference between new wheelset and 1st ∼ 3rd worn wheelset can be kept below 21%, 52% and 9% respectively. In this case, the equivalent conicity is closest to the initial state and reaches a steady state, which will not change significantly with the radius further increasing. Viewed from the aspects of reducing wheel wear, avoiding wheel flange contact and keeping conicity stable simultaneously, the minimum radius of horizontal curve should be limited to 800 m. The research results validate the minimum curve radius suggested in Code for Design of Heavy-haul Railway in China, and provide a scientific explanation for the determination of this value.

Importance of building inspection on the seismic response of a severely damaged RC structure during the February 6, 2023 Kahramanmaraş earthquake sequence

Large magnitude February 6, 2023 earthquakes in Türkiye created a devastating effect on the building stock on a vast region. For earthquakes of this magnitude, severe damage and collapses are indispensable to the old building stock with deficiencies certified in previous earthquakes. But unexpectedly, the newly constructed buildings that were designed by recent version of Turkish Building Seismic Code (TBEC 2018) also experienced severe damage. After conducting site investigations on one of the recently constructed and severely damaged RC building, a detailed numerical study was performed to identify the reasons for the observed seismic damage. This study pinpoints the main cause of such damage due to lack of thorough building inspections during construction to ensure the implementation of the seismic reinforcement detailing specified in blueprints for providing required ductility, as revealed by field investigations. Additionally, it identifies potential issues stemming from a lack of full comprehension of the seismic design philosophy within the code. The existing design pushes the limits on the axial load level on slender column elements and fall short in capturing the soft story irregularity. Although there is a soft base story in the investigated building, using structural walls only in one direction with moderately confined boundary zones increased its vulnerability. This example shows that in Türkiye, where seismic activity is very high and quite lethal, seismic design codes should set stricter limits and measures, and building inspection system must be strictly enforced.

Interpretable machine learning model for shear strength estimation of circular concrete‐filled steel tubes

SummaryPrecise estimation of the shear strength of concrete‐filled steel tubes (CFSTs) is a crucial requirement for the design of these members. The existing design codes and empirical equations are inconsistent in predicting the shear strength of these members. This paper provides a data‐driven approach for the shear strength estimation of circular CFSTs. For this purpose, the authors evaluated and compared the performance of nine machine learning (ML) methods, namely linear regression, decision tree (DT), k‐nearest neighbors (KNN), support vector regression (SVR), random forest (RF), bagging regression (BR), adaptive boosting (AdaBoost), gradient boosting regression tree (GBRT), and extreme gradient boosting (XGBoost) in estimating the shear strength of CFSTs on an experimental database compiled from the results of 230 shear tests on CFSTs in the literature. For each model, hyperparameter tuning was performed by conducting a grid search in combination with k‐fold cross‐validation (CV). Comparing the nine methods in terms of several performance measures showed that the XGBoost model was the most accurate in predicting the shear strength of CFSTs. This model also showed superior accuracy in predicting the shear strength of CFSTs when compared to the formulas provided in design codes and the existing empirical equations. The Shapley Additive exPlanations (SHAP) technique was also used to interpret the results of the XGBoost model. Using SHAP, the features with the greatest impact on the shear strength of CFSTs were found to be the cross‐sectional area of the steel tube, the axial load ratio, and the shear span ratio, in that order.

Optimization of White Box Testing by Utilizing Branching and Repeating Structures in Java Programs Using Base Path

Software testing is a process created to detect anomalies in the operation of a program or system in order to achieve the expected results. White box testing is a software testing method that tests the internal structure, design and program code. This research aims to produce an optimization method for white box testing in Java programs by utilizing branching and repetition structures using the basis path method, as well as analyzing the effectiveness of the proposed method in generating test cases. The Java program tested in this research includes input function calls, loops, branching, and exception handling. Test case design is carried out by applying the basis path method to achieve comprehensive coverage. The test results show that the base path method is able to produce effective test cases for testing control structures without redundancy. Test case design is assisted by flowgraph and matrix graph modeling. It is hoped that this research can contribute to the optimization of white box testing techniques.

Classification and ultimate capacity of duplex stainless steel H-section under cyclic loading

Stainless steel materials are high ductility and strain hardening under cyclic loading, which is promising in seismic design. However, the current European stainless steel structure design code prEN 1993-1-4(EC3) ignores this favorable effect in the cross-section classification, as well as the lack of prediction formulas for the ultimate capacity of H-section under cyclic loading. In this paper, parametric analysis was carried out for H-section to extend the database based on the existing test results after calibration of the finite element model. The cross-section classification criteria of duplex stainless steel beams and beam-columns around major-axis under cyclic loading were investigated, and the EC3 classification of stainless steel H-section was evaluated. The predicted results for EC3 are conservative due to not considering the constraints of the cross-section component plates and the favorable conditions for the material strengthening of stainless steel under cyclic loading. Based on this, classification criteria for stainless steel H-section under cyclic loading were proposed and summarized. Subsequently, the method of calculating the ultimate capacity methods under cyclic loading suggested by EC3, Chen and Zhou et al. were evaluated. The results show that EC3 is on the conservative side, with actual results being generally 1.5 times higher than the predictions. In contrast, Chen and Zhou et al.'s method is on the unsafe side of the prediction. Finally, improvement suggestions are given for EC3 and the continuous strength method by considering the over-strength factor under cyclic loading, respectively, with results exhibiting high accuracy.

Seismic response modification factors of single-layer diamatic dome structures

In this research, the seismic behavior of single-layer diamatic dome (SLDD) structures was analyzed under earthquake loads, and then the seismic response modification factors (SRMFs) of these structures were extracted. For this purpose, 16 models with different span lengths (SLs) and rise-to-span ratios (RSRs) were designed, and the effects of SL and RSR on the SRMFs of these structures were evaluated. Also, the effect of member density on the SRMFs was studied. The models were first designed under the applied loads based on relevant design codes. Then, by performing the nonlinear time history analyses using the three translational components of ground motion records, the control point and target displacement in the horizontal and vertical directions were obtained to implement the pushover analyses. Thereafter, the pushover analyses were implemented by using the target displacements derived from the nonlinear time history analyses, and the SRMFs of SLDD structures in both horizontal and vertical directions were obtained. The results indicate that models with RSRs of 1/7 to 1/3 remained in the elastic range in the horizontal direction. For the models with an RSR greater than 1/3, if the RSR increases, the ductility and behavior factor increases in the horizontal direction. However, there is a downward trend in the vertical direction due to the increase in the vertical stiffness. The horizontal and vertical behavior factor was obtained in the range of 1.155–2.459 and 1.155–2.893, respectively. Finally, by using the results obtained and through the nonlinear regression analysis, equations were proposed for the period, target displacement, displacement amplification factor, and behavior factor for SLDD structures in terms of the SL and RSR in the horizontal and vertical directions.

Reliability-based calibration of companion load combination factors by considering concurrent wind and ice loading for structural design

Transmission towers and overhead transmission lines are designed and constructed by considering the combined ice load and wind-on-ice load if the ice accretion hazard is not negligible. The structural design codes provide clauses with a range of values to evaluate such a combined load. However, it is unclear which of the values suggested in the codes one should use for specified regions, and the reliability-based calibration of such a combination is unavailable. To fill this gap, in the present study, we carried out the reliability-based calibration of the companion load combination factors by using statistics of the ice accretion thickness and concurrent wind speed available from more than 250 meteorological stations in Canada. For the calibration, a nonlinear combination problem needs to be considered since the wind-on-ice load depends on the accreted ice thickness, making this calibration task differ from those commonly reported in the literature, which is focused on the linear load combination problem. A parametric investigation was also carried out to assess the effect of using different return periods and the correlation between ice accretion and concurrent wind speed on the companion load combination factors. The calibration results were used to recommend the load combination format, the companion load combination factors, and the ratio of the square equivalent concurrent wind speed to the return period value of the annual maximum wind speed, which is commonly implemented in design codes.

The Impact of Change Orders Caused by Legislative Changes on Program Management in the UAE Construction Industry

Program management is an important strategy for organizing and managing multiple interdependent construction projects to achieve strategic goals. However, when change orders occur, they can have a serious impact on the quality, time, cost of projects and, ultimately, affect the construction program. Furthermore, when change orders are caused particularly by legislative changes, such as environmental laws, taxes, tolls, safety codes, transportation, design or building codes, their impacts are unavoidable, yet can be managed through mitigation strategies. The existing literature only reports the implications of change orders on the project level and reports legislative changes as one of the contributing factors to change orders, but does not consider the implications on a program level. This study aims to close this knowledge gap by assessing the implications of change orders caused by legislative changes on program management in the construction industry during the construction phase, and explore what the possible mitigation strategies to manage change orders caused by legislative changes are. The objectives of the study include identifying the implications of change orders on construction projects in the UAE through a literature review using peer-reviewed journals and reliable industry sources. Additionally, we investigate the implications of change orders caused by legislative changes on construction programs through interviewing subject matter experts, evaluating the importance of the reported impacts, with possible mitigation strategies, through a structured questionnaire and Relative Importance Index (RII) and, finally, proposing a set of recommendations for key industry stakeholders. A mixed methods approach is adopted in this qualitative study, and the participants include clients, contractors and consultants from the construction industry, with a defined scope covering the construction stage only. The outcomes of the study can guide program managers, decision-makers and practitioners in the construction industry to successfully deliver all projects by directing proper resources to accommodate legislative changes.

STRENGTH DESIGN OF REINFORCED CONCRETE SECTIONS BASED ON A NUMERICAL OPTIMIZATION METHOD

Reinforced concrete structures are widely used in construction of civil infrastructures. Classical methods are available for the analysis and design of reinforced concrete members, such as beams or columns, which are typically done by hand or using a spreadsheet program. In this study, an analysis and design approach of reinforced concrete sections is developed based on a numerical optimization method, and applied in accordance with the latest concrete design code. The basic idea of the proposed approach is to derive an optimization formulation in order to determine the minimum steel area required to support a given factored load combinations applied on a concrete section. A rigorously derived analysis and design framework of general beam sections is presented. For practical applications by civil and structural engineers, the readily-available optimization solver in Microsoft Excel spreadsheet is used. To illustrate the applicability of the approach, a numerical example with different analysis and design cases is studied. The proposed analysis and design approach using numerical optimization and spreadsheet solver works very well and is easy to implement in the Excel environment. The analysis and design results compare well with hand calculation results based on the classical method.

Field testing performance of prebored precast piles with enlarged base in soft ground

Prebored precast piles with an enlarged base (PPEB piles) are constructed using an innovative and environmentally sustainable method, which notably reduces noise, soil squeezing, and mud discharge. Although PPEB piles have been widely applied in many cities in China, their bearing performance, including side friction and end resistances, on soft ground remains relatively unelucidated. This paper focuses on case studies of vertical-bearing PPEB piles based on a group of vertical static load field tests in Shanghai. The following conclusions are drawn: (1) Compared with traditional hammered-driven piles, PPEB piles exhibit better construction quality and load-bearing performance, as well as a relatively slow increment of settlement even under ultimate loading. (2) The resistance of the enlarged base section of the PPEB pile was approximately 16.3% of the total resistance under ultimate loading. (3) Compared with the values proposed in the Shanghai Foundation Design Code, the side friction resistance of the PPEB pile in deep silty sand (34.5–39 m) exhibited a considerable increase of approximately 156%. Additionally, the side friction in the soft ground was close to the values proposed in code. The case studies provide practical guidelines for the application of PPEB piles in soft ground.

STRENGTH DESIGN OF REINFORCED CONCRETE SECTIONS BASED ON A NUMERICAL OPTIMIZATION METHOD

Reinforced concrete structures are widely used in construction of civil infrastructures. Classical methods are available for the analysis and design of reinforced concrete members, such as beams or columns, which are typically done by hand or using a spreadsheet program. In this study, an analysis and design approach of reinforced concrete sections is developed based on a numerical optimization method, and applied in accordance with the latest concrete design code. The basic idea of the proposed approach is to derive an optimization formulation in order to determine the minimum steel area required to support a given factored load combinations applied on a concrete section. A rigorously derived analysis and design framework of general beam sections is presented. For practical applications by civil and structural engineers, the readily-available optimization solver in Microsoft Excel spreadsheet is used. To illustrate the applicability of the approach, a numerical example with different analysis and design cases is studied. The proposed analysis and design approach using numerical optimization and spreadsheet solver works very well and is easy to implement in the Excel environment. The analysis and design results compare well with hand calculation results based on the classical method.

NUMERICAL MODELLING OF STRUCTURAL BAMBOO UNDER COMPRESSION

Bamboo is a sustainable and eco-friendly material with great potential to replace traditionally available construction materials like concrete and steel. However, accurately predicting the behavior of bamboo is essential for improving the structural design codes, which will enhance the wider usage of bamboo as a structural member. In this study, the buckling of bamboo is modelled numerically as both cylindrical and tapered circular columns with varying elastic moduli across the cross-sections in ABAQUS. Then, the results were compared with Euler's equation derived for the cylindrical and tapered circular columns having homogeneous cross-sections. Finally, it was observed that columns with varying elastic moduli across the cross-section have 1.5 to 2.3 times a lesser buckling load capacity than columns with homogeneous cross-sections with outer Young's modulus value (Eo). Also, compared to buckling load homogeneous cross-sections with inner Young's modulus value (Ei), varying elastic modulus cross-sections have 1.7 to 2.7 times higher buckling load. This study emphasizes the necessity of having a simple analytical equation with varying elastic modulus for calculating the buckling load for bamboo columns.

NUMERICAL MODELLING OF STRUCTURAL BAMBOO UNDER COMPRESSION

Bamboo is a sustainable and eco-friendly material with great potential to replace traditionally available construction materials like concrete and steel. However, accurately predicting the behavior of bamboo is essential for improving the structural design codes, which will enhance the wider usage of bamboo as a structural member. In this study, the buckling of bamboo is modelled numerically as both cylindrical and tapered circular columns with varying elastic moduli across the cross-sections in ABAQUS. Then, the results were compared with Euler's equation derived for the cylindrical and tapered circular columns having homogeneous cross-sections. Finally, it was observed that columns with varying elastic moduli across the cross-section have 1.5 to 2.3 times a lesser buckling load capacity than columns with homogeneous cross-sections with outer Young's modulus value (Eo). Also, compared to buckling load homogeneous cross-sections with inner Young's modulus value (Ei), varying elastic modulus cross-sections have 1.7 to 2.7 times higher buckling load. This study emphasizes the necessity of having a simple analytical equation with varying elastic modulus for calculating the buckling load for bamboo columns.

A Hybrid Neural Coding Approach for Pattern Recognition With Spiking Neural Networks.

Recently, brain-inspired spiking neural networks (SNNs) have demonstrated promising capabilities in solving pattern recognition tasks. However, these SNNs are grounded on homogeneous neurons that utilize a uniform neural coding for information representation. Given that each neural coding scheme possesses its own merits and drawbacks, these SNNs encounter challenges in achieving optimal performance such as accuracy, response time, efficiency, and robustness, all of which are crucial for practical applications. In this study, we argue that SNN architectures should be holistically designed to incorporate heterogeneous coding schemes. As an initial exploration in this direction, we propose a hybrid neural coding and learning framework, which encompasses a neural coding zoo with diverse neural coding schemes discovered in neuroscience. Additionally, it incorporates a flexible neural coding assignment strategy to accommodate task-specific requirements, along with novel layer-wise learning methods to effectively implement hybrid coding SNNs. We demonstrate the superiority of the proposed framework on image classification and sound localization tasks. Specifically, the proposed hybrid coding SNNs achieve comparable accuracy to state-of-the-art SNNs, while exhibiting significantly reduced inference latency and energy consumption, as well as high noise robustness. This study yields valuable insights into hybrid neural coding designs, paving the way for developing high-performance neuromorphic systems.

Influence of thermal fatigue cycles on concrete cold joints

Mass concrete structures in northern climates experience extreme oscillations in temperature each year. These fluctuating conditions incur large thermal stresses, which are of particular concern at cold joint locations. To better understand the behaviour of cold joints subjected to these thermal fatigue cycles, an experimental program was conducted at the University of Manitoba, focusing on the performance of concrete cylinders with concrete-to-concrete interfaces. Specimens were prepared with joints oriented either horizontally to evaluate direct tensile performance or at a 35°, 40°, or 45° angle for slant shear. These cylinders were then installed in specially designed vertical translation-restricting frames and placed in an environmental chamber, where they were subjected to temperatures cycling between −25 °C and 40 °C. Static testing after 50, 150, and 250 cycles was performed to ascertain remaining bond strength. An increase in performance of approximately 20 % was observed in direct tension after 50 cycles, followed by a subsequent decrease. In general, the thermal fatigue cycles did not appear to detrimentally impact bond strength after 250 cycles in both direct tension and slant shear. Additionally, interface friction demonstrated no meaningful trend between specimens that had experienced zero to 250 cycles, remaining relatively consistent with their corresponding roughness level defined in the Canadian Design of Concrete Structures code, and bond cohesion appeared to follow a similar trend to mean direct tensile bond strength results.

Enhancing Seismic Performance: A Comprehensive Study on Masonry and Reinforced Concrete Structures Considering Soil Properties and Environmental Impact Assessment

Approximately 20,000 people are killed annually on average by building and infrastructure collapses and failures caused by seismic activities. In earlier times, seismic design codes and specifications set minimal requirements for life safety performance levels. Earthquakes can be thought of as recurring events in seismically active areas, with severity states ranging from serviceability to ultimate levels. Buildings designed in accordance with site-specific response spectra, which take into account soil properties based on ground motion amplification data, are better at withstanding such forces and serving their design purposes. This study aims to investigate the site response of reinforced and masonry buildings, considering the effect of soil properties based on the amplification of ground motion data, and to compare the life cycle assessment of the buildings under consideration based on the design and the site-specific response spectrum. In terms of soil properties and site-specific response spectra, STRATA is used to determine the site-specific response for the considered locations for a return period of 475 years for 100 realizations based on the randomization of site properties. For structural analysis, AxisVM software, which is a compatible finite element analysis, is used for building design and analysis, generating comparative results based on the design- and site-specific spectra. To determine and identify potential failures in the model, response spectra were applied to understand the difference in horizontal deflection in two different instances (for elastic design- and site-specific spectra). After building design and analysis is performed, a life cycle analysis in terms of environmental impact assesments using OpenLCA and IdematLightLCA is done. This is done to ascertain the additional expenses in terms of ecocosts and carbon footprints on some failed elements in the structure which are required to make the buildings more resilient when the site-specific response spectrum is applied and to compare the potential economic losses that may occur based on ecological costs. The study presents a comprehensive investigation into the seismic response of masonry and reinforced concrete buildings in Győr, Hungary, incorporating advanced geophysical techniques like multichannel surface wave (MASW) and structural analysis software, AxisVM. Additionally, tailored retrofitting strategies are explored to enhance structural resilience in seismic-prone regions. Significant ground amplifications in soil properties across different profiles are revealed, emphasizing the effectiveness of these strategies in reducing structural deflection and improving resilience. Highlights of the results are observed where the site-specific response spectra are higher than the EC8 design response spectrum. Furthermore, the research underscores the substantial environmental impact, considering both ecocosts and CO2 emissions associated with retrofitting measures, highlighting the importance of sustainable structural interventions in mitigating seismic risks.

Identifying the effect of thickness on crack width in one-way reinforced concrete slab structures

This paper presents an evaluation study of crack limit states according to design codes and previous research. It aims primarily to relate research findings to design code similarities. Cracks in reinforced concrete structures are still a challenging problem for researchers, especially in one-way plate structures where there is still a lot of damage and corrosion in the reinforcement due to cracks. Finding the right formula will make it easier for practitioners to design these structures, and the problem of durability in reinforced concrete plates can be overcome. From this research, an approach is proposed on how to predict the maximum crack width formula in one-way reinforced concrete slabs with different thicknesses. Plates use a variety of thicknesses, including 125 mm, 150 mm, 175 mm, and 200 mm. The test specimens have the same dimensions and steel reinforcement, a slab width of 0.6 m and a length of 2 m. From a literature study of prediction formulas from previous research works and codes, namely wmax(prop)=7.5*10-3 fsh-0.333, it was found that thickness (h) has little influence on maximum crack width. The results from both approaches in this analysis are overall in accordance with the observed experimental tests and the proposed formula. Based on these observations, increasing the thickness of the reinforced concrete slab has significantly reduced the maximum crack width so that the experimental formula is obtained, namely wmax(exp)=0.32*fsh-1.113. Therefore, a constant is needed to evaluate the influence of thickness parameters for slabs with a thickness less than 200 mm on the maximum crack width formula for reinforced concrete slabs, and a special approximation formula has been obtained. In practical use, the crack width formula can only be used for one-way slabs

A Comparative Study of Rectangular Beam Depth Effects Under EBCS-1995 and ES EN-2015 Codes

To achieve structural integrity, serviceability, and economy of buildings, national and international building standards are used for dimensioning and proportioning of structural members. Building codes may be amended due to, the existence of new construction materials, technologies, and structures, and to improve earlier gaps. Ethiopia has experienced three building codes in the last 40 years. Those codes were the Ethiopian Standard Code of Practice, ESCP 1983-1995, Ethiopian Building Code of Standard, EBCS-1995, and the Ethiopian Standard, ES EN 2015. Design code compliance design and supervision of buildings is one of the major ways to achieve the planning, design, construction, service life as well as overall performance of projects. This study is conducted on the depth determination of an interior RC beam with different span and steel grades under EBCS-1995 and ES EN-2015 design codes. The result of this study proves that EBCS 1995 is uneconomical for shear and moment design for longer spans, and preferable for smaller spans, while ES EN 2015 provides smaller serviceable depth and deflection and maintains economical design for longer spans. Construction professionals need to understand the basic purpose of code amendment and should use the new design code as a major design reference and the earlier code accordingly.

Selection of optimal intensity measures for seismic performance evaluation of underground utility tunnel and internal pipeline system

Seismic intensity measures (IMs), which are closely related to both earthquake hazards and structural responses, play a critical role in the performance-based earthquake engineering (PBEE) framework. This paper aims to investigate and define the most representative IMs for probabilistic seismic demand model (PSDM) for the longitudinal utility tunnel and internal pipeline system. Similar to the requirements by the Chinese Code for seismic design of urban rail transit structures, the utility tunnel in this study is assumed being buried in four typical engineering site classes for the analyses. Soil-tunnel-pipeline interactions are simulated using a double-beam system resting on a nonlinear foundation. Soil-tunnel interaction, tunnel-pipeline interaction and joint connections are modeled as nonlinear springs with different mechanical properties. A series of 17 pairs of outcrop ground-motion records and 27 commonly used IMs are selected in the analyses. Engineering demand parameter (EDP) is defined based on the maximum joint opening and the maximum strain of the utility tunnel and internal pipeline, respectively. The selected IMs for predicting the seismic responses of tunnel-pipeline systems are tested using different criteria, i.e., correction, efficiency, practicality, and proficiency. The final decision-making procedure employs a fuzzy multi-criteria decision method. The numerical results indicate that: (1) The velocity-related IMs are the most representative IMs based on the four criteria for structures buried in four sites of different conditions; (2) The optimal seismic IMs vary with different criteria, site classes and structure types. According to the fuzzy multi-criteria decision approach, optimal IMs for the tunnel-pipeline system are PGV, PGV, EPV and HI for site classes I – IV, respectively. The proposed optimal IMs can be utilized to construct seismic fragility curves of utility tunnel, internal pipeline and tunnel-pipeline systems in four different site classes.

Global sensitivity analysis of the maximum live load and its applications

The design live loads are determined by the probability distribution of the maximum live load, which is influenced by the amplitudes and time intervals of various sustained and extraordinary loads. If the relative impact of different input variables on the maximum can be clarified, more targeted load surveys and modeling can be achieved. However, there is currently no global sensitivity analysis that simultaneously considers all input variables. In this study, the probability density function of the maximum live load is determined using the load coincidence principle and probability density evolution method. The relative entropy is employed as a measure for conducting a global sensitivity analysis across five common building occupancy types. The results indicate a significant imbalance in the impact of different input variables. The load amplitudes have a much greater effect than the time intervals. Among various load amplitudes, those related to the extraordinary loads often have the most significant impact. Regarding the time intervals, the occurrence intervals corresponding to the extraordinary loads caused by furniture stacking and normal crowding consistently have the least influence. For the time intervals with minimal impact, it is suggested to treat them as deterministic values in the live load modeling. This treatment has a negligible impact (not exceeding 10%) on the mean and upper fractile of the maximum, which are generally used for design in load codes.