Strain Demands Research Articles

New Methods for Predicting Strain Demand of Arctic Gas Pipelines across Permafrost under Frost Heave Displacement

With increasing gas resource development in the Arctic region, gas pipeline installations in permafrost regions are becoming important. Frost heave of pipeline foundation soils may occur when a chilled gas pipeline passes through unfrozen areas with frost-susceptible soils. The stress and strain behaviors caused by the differential frost heave will directly affect the safety of the pipeline. A nonlinear finite element model (FEM) computing the mechanical responses of the buried gas pipeline subjected to frost heave load was established and successfully validated with the results of a large-scale indoor pipe-soil interaction experiment carried out in Caen in France. Utilizing C# language and object-oriented visual programming techniques, a new customized parametric strain calculation software was developed. The effects of pipe diameter, pipe wall thickness, pipe internal pressure, and peak soil resistance on the longitudinal strain of X60, X70, and X80 steel pipes have been investigated quantitatively. For the first time, a fitting semiempirical equation and trained backpropagation neural network (BPNN) for predicting pipeline strain demand subjected to frost heave load were proposed based on 2688 groups of FEM results. The comparison results have proved their high accuracy and lower running time cost. The proposed new methods can be applied in the strain-based pipeline design and safety evaluation of pipelines in service. It is in the hope of supplementing existing theory and identifying new approaches for arctic gas pipeline installations.

Introduction: Occupational Hazards to the Joint Replacement Surgeon

Introduction: Occupational Hazards to the Joint Replacement Surgeon

Determining the effective slab width of composite joint with the weak-axis connection for ultimate bearing capacity

Extensive brittle failures on the weld zone of beam bottom flange in composite joints of SMRFs were observed during the Northridge earthquake. One of the main reasons is the sizeable tensile strain demand generated at the beam bottom flange zone under sagging bending. The key to accurately understanding the mechanical properties of composite joints is the effective width of the slab. However, the previous research is all aimed at the I-section composited joints with column strong-axis connection or CFST column connection. Therefore, the research conclusions may not suit the composited joint with the weak-axis connection. Beam column weak axis connection is as universal as the strong axis connection. Therefore, this paper used ABAQUS software to investigate the effective width of the slab in composited joints with the weak-axis connection. Firstly, it defines the ultimate state of bearing capacity corresponding to the analysis in this paper. Secondly, it investigates the influence factor on the effective width of the slab under the ultimate sagging moment and hogging moment. Thirdly, it uses Gray Correlation Theory and MATLAB to fit the calculation formula of the effective width of the slab under the ultimate sagging moment and hogging moment. Fourthly, it compares the slab's effective flange width in the previous experiment and the formula presented in the paper. Finally, analyze the applicability of the fitting formula to the strong axis rigid composite joints and T-shaped rigid composite joints of the I-shaped column and H-beams.

Adaptive strategies of uropathogenic Escherichia coli CFT073: from growth in lab media to virulence during host cell adhesion.

Urinary tract infections (UTIs) are a major concern in public health. The prevalent uropathogenic bacterium in healthcare settings is Escherichia coli. The increasing rate of antibiotic-resistant strains demands studies to understand E. coli pathogenesis to drive the development of new therapeutic approaches. This study compared the gene expression profile of selected target genes in the prototype uropathogenic E. coli (UPEC) strain CFT073 grown in Luria Bertani (LB), artificial urine (AU), and during adhesion to host bladder cells by semi-quantitative real-time PCR (RT-PCR) assays. AU effectively supported the growth of strain CFT073 as well as other E. coli strains with different lifestyles, thereby confirming the appropriateness of this medium for in vitro models. Unexpectedly, gene expression of strain CFT073 in LB and AU was quite similar; conversely, during the adhesion assay, adhesins and porins were upregulated, while key global regulators were downregulated with respect to lab media. Interestingly, fimH and papGII genes were significantly expressed in all tested conditions. Taken together, these results provide for the first time insights of the metabolic and pathogenic profile of strain CFT073 during the essential phase of host cell adhesion.

Experimental and numerical study of square HSS BIEs under cyclic loading

Braces with Intentional Eccentricity (BIEs) have recently been introduced as an alternative to traditional Concentrically Loaded Braces (CLBs) whose performance may overcome some of the shortcomings of the latter. It is postulated that the onset of local buckling in BIEs is delayed owing to a more even distribution of the strain demands under compression loading. Further, the significant post-yielding stiffness of the system can provide control over the predicted displacement levels under the action of the design earthquake. In this article, the results of the testing of four full-scale square ASTM A1085 HSS BIE specimens subjected to reversed cyclic loading are presented. The HSS members and eccentricities were selected with the intention of comparing the response of braces complying with and exceeding the CSA S16-14 global and local slenderness limits. The introduction of the eccentricity was achieved by means of side plates linking the HSS to bolted knife and gusset plate assembly connections. The experimental program is expanded and complemented with finite element analyses of additional BIE and CLB models. The experimental and numerical results show that the BIEs’ response displays the purported benefits of the introduction of the eccentricity. However, it was also found that fracture due to the rotational demand under tensile load at the bracing member’s ends can govern the failure mode of BIEs that are more resistant to developing local buckling at mid-length. The implications of the results to the design of Frames with Intentionally Eccentric Braces (FIEBs) are discussed.

Cyclic behavior of SMA slip friction damper

This paper proposes a new type of self-centering (SC) damper which exploits the shape memory alloy (SMA) bolts and variable friction mechanism, termed the SMA slip friction damper (SMASFD). The theoretical equations governing the force–displacement relationship, the equivalent stiffness and the equivalent viscous damping are first derived. Then, the application potential of such damper is briefly discussed. In the experimental study, the results of the experimental validations of the SMA bolts and the friction mechanism are presented, followed by the results of proof-of-concept test on the fabricated SMASFDs. According to the testing results, the damper exhibited a symmetric tension–compression flag-shaped hysteresis characterized by excellent SC capacity and good damping capability. The prestrain treatment was applied to the SMA bolts in one test, which was found effectively increased the initial stiffness of the damper. To provide a further understanding on the damper and examine the stress and strain demands of the components, high-fidelity finite element models were established for numerical simulations. Both the analytical method and numerical simulation were validated by the experimental data.

A Proposal for a Simple Method for Determining the Concrete Slab Width of Composite Beam-to-Column Joints

Extensive brittle failures in the weld zone of the beam bottom flange in composite joints of SMRFs were observed during the Northridge earthquake and the Kobe earthquake. One of the main reasons is the large tensile strain demand generated at the beam bottom flange zone under positive bending. The key to accurately understanding the mechanical properties of composite joints is the effective width of the slab. However, researchers have no consensus on the flange slab’s effective width for composite joints, even with the simplest solid concrete slab. Therefore, the best way to design the composite joint specimen is by following the current design specifications. However, each specification implements different ideas and approaches for specifying an effective slab width. This paper presents comparisons of the effective flange width provisions in China, the United States, Australia/New Zealand, and the European Union. The characteristics of each provision are briefly described and summarized. Numerical comparisons for positive and negative moment regions of continuous spans follow. Based on the commonalities and main differences among all these provisions, we propose a recommended equation for calculating the effective width of a solid concrete slab, reflecting the specification differences. The reliability of the recommended equation was verified with ABAQUS software analysis. The recommended equation can meet the fast and secure design requirements for composite joints in tests with concrete slabs.

Strength matching factor of pipeline girth weld designed by reliability method

Crack-like defects frequently form in pipes exposed to aggressive environments or during welding fabrication. Appropriate strength matching factors should be determined for welding process evaluation based on the reliability aspect. In this paper, the current research status of codes and standards related to the strength requirement of weld metals in the pipeline industry were reviewed. The results showed that almost all standards considered the lower limit of pipe tensile strength as a requirement for weld strength evaluation for specimens of cross-weld test breaking at the weld position. This was contradictory to the original intention of even-match or over-match of pipeline girth weld. The Monte Carlo Method was then employed to investigate the evolution of girth weld strength matching factor and pipeline failure probability under different high-low misalignments, fracture toughnesses, and standard deviations of pipe strength distribution. The data revealed significantly reduced probability of pipe failure as the weld metal strength matching factor increased. At the same strength matching factor, the failure probability of pipe decreased as fracture toughness of girth weld. The failure probability of pipe also declined as the misalignment and standard deviation of pipe strength distribution diminished. Based on the requirement of certain target reliability and strain demand, a semi-empirical prediction model of critical strength matching factor was proposed for engineering applications. The analysis of parameter sensitivity showed the relative importance of several parameters on the critical strength matching factor of girth weld, including high-low misalignment, standard deviation of pipe material strength distribution, and fracture toughness.

Experimental and Finite Element Study of Polymer Infilled Tube-in-Tube Buckling Restrained Brace

This study presents a tube-in-tube buckling-restrained brace (BRB) infilled with lightweight and rapid hardening polymer. The proposed BRB consists of a circular or square tube core encased with a tube of similar shape and polymer infill. The tube-in-tube arrangement minimizes the filler material volume and enables the use of rolled steel section as opposed to welded profiles commonly utilized when large BRB axial strength is required, although welded profiles suffer from low assembly accuracy resulting from welding deformation. The infilled polymer has a density of approximately half that of mortar and requires a curing time of 24 h, enabling weight and fabrication time reduction. The stability and inelastic deformation capability of the BRB were investigated through brace and subassembly tests of six circular and four-square full-scale specimens, followed by finite element analysis. The test results show that circular BRB designed with a Pcr/Py ratio of 1.46 exhibited a stable hysteresis up to 1.42% and 1.06% core strain in tension and compression, respectively. Circular and square specimens designed with Pcr/Py ratios ranging from 0.82 to 1.06 exhibited stable hysteresis before failing by global buckling at compressive core stains ranging from 0.86% to 1.09%. The slot weld detail adopted for welding core projection stiffener displayed a stable performance in circular BRB specimens, while it resulted in large plastic strain demand in square BRB specimens, leading to core fracture at tensile core strains ranging from 0.64% to 0.71%.

Strain demand of elastic pipes subjected to permanent ground displacements using the finite difference method

Long-distance pipelines are one of the primary means of oil and gas transportation. During the construction process, long-distance pipelines are inevitably buried across geohazard zones, which potentially generate permanent ground displacements. These ground displacements can potentially induce excessive strains in the pipe posing a great threat to the pipe’s safety and integrity. In this study, a new numerical methodology for the response analysis of pipes subjected to ground displacements is proposed based on the finite difference method. Simulating the pipeline as a large deformation Euler Bernoulli beam, the finite difference method is used to solve the two interacting nonlinear differential equations of equilibrium in the longitudinal and lateral directions considering the nonlinear pipe-soil interaction induced by the ground displacement. Implemented using the nonlinear equation solver of FindRoot by Mathematica for solving nonlinear equations, the longitudinal strain along the pipeline can be subsequently derived, and the tensile and compressive strain demands can be therefore determined for engineering reference. Finally, the applicability of this method is validated based on two hypothetical study cases involving symmetric and non-symmetric soil resistance on the lateral direction of the pipe. Comparing the results with the finite element analysis solver Abaqus, we demonstrate that this present methodology has excellent predictive capabilities. Our study is carried out for elastic response calculation, but the proposed method shows a great promise for further development involving material nonlinearity, which is appropriate for the preliminary safety evaluation for the design of new pipelines or for risk prescreening of existing pipelines.

Three-dimensional finite element modeling of RC columns subjected to cyclic lateral loading

This paper presents a detailed finite element modeling scheme to simulate the cyclic response of RC columns considering low-cycle fatigue and bond-slip of reinforcement. The modeling scheme includes a triaxial constitutive model recently proposed in the literature to simulate concrete failure under cyclic loading. For steel, a commonly used uniaxial model is enhanced to account for bar rupture using a new low-cycle fatigue criterion, which has been validated with data from fatigue tests on reinforcing bars. The bond-slip behavior of vertical reinforcing bars is modeled using a zero-thickness concrete-steel interface element. The interface element has a bond stress-slip constitutive law that predicts bond deterioration caused by generalized slip demands, tensile yielding of steel, and compression damage in concrete. The finite element models are validated with experimental data from cyclic tests on large-scale column and pile specimens which exhibited flexure-dominated responses. The models accurately simulate the lateral force–displacement response and failure of the specimens, and provide peak tensile strain demands along longitudinal bars which are similar to those measured experimentally. Sensitivity analyses are also conducted to study the effect of modeling assumptions related to low-cycle fatigue and bond-slip behavior.

Effect of material regularization in plastic hinge integration analysis of slender planar RC walls

Recently, mesh-objective (i.e., mesh insensitive) fiber-based numerical models have been developed to simulate RC walls with compression-controlled softening failure modes (i.e., concrete crushing and rebar buckling). These models regularize the post-peak stress-strain behavior of concrete and steel materials based on experimentally-calibrated failure energy equations. While the ultimate displacements of RC walls predicted by these models have been accurate, the local curvature and material strain demands are very sensitive to the selected mesh. Consequently, subsequent normalization of the section curvatures based on an assumed plastic hinge length has been proposed in the literature, resulting in a two-step analysis process. This normalization step uses approximate equations that are dependent on the structural configuration and that can be challenging to implement in cyclic analysis. In accordance with these limitations, this paper studies the effect of material regularization in force-based beam-column elements with a plastic hinge integration method to accurately simulate, in a one-step process, the softening behavior of slender planar RC walls under lateral loading. Numerical results are evaluated using available experimental measurements of eight slender flexural walls with compression-controlled failure modes from the literature. Previous research has shown that one of the biggest limitations of using conventional material models (i.e., without regularization of the stress-strain curves) is that the predicted ultimate displacements are significantly sensitive to the length of the critical integration point over which the nonlinear strains concentrate. This paper demonstrates that this sensitivity of the analysis results can be significantly reduced by using regularized material models and a plastic hinge integration method over a wide range of assumed plastic hinge lengths. The combination of material regularization and plastic hinge integration analysis can also predict the section curvatures and strains of RC walls, with no need for a separate normalization step, though these local responses are more sensitive to the assumed plastic hinge length.

Enhancing the Performance of Knee Beam\u2013Column Joint Using Hybrid Fibers Reinforced Concrete

The knee beam–column joint is a critical location in a Reinforced Concrete (RC) structure particularly when subjected to earthquake vibrations. The current structural design codes dictate the use of high amounts of steel reinforcements in the frame joint to manage large strain demands in seismic-prone regions. However, these codes could result in the congestion of steel reinforcements in the limited joint area which can consequently produce numerous construction complications. This study aims to improve the structural performance of Knee Joint (KJ) by reducing the load induced to the embedded steel reinforcements during seismic vibrations. Hence, this study attempted to develop a Hybrid Fiber Reinforced Concrete (HyFRC) by combining multiple synthetic fibers to be introduced onto KJ. Six KJ specimens were cast using five developed HyFRC materials and one Control specimen to be experimentally tested under lateral cyclic loading. The results indicated significant improvements for the HyFRC KJ specimens particularly in energy dissipation capacity, stiffness degradation rate, displacement ductility toughness, steel reinforcement strain and hysteretic behavior. A total of six Finite Element (FE) KJ models were developed using the HyFRC materials to verify the results from the experimental testing. The accuracy of the proposed FE models resulted in average percentage differences of 25.89% for peak load, 3.45% for peak load displacement and 0.18% for maximum displacements from the experimental data. In conclusion, this study developed HyFRC materials that are beneficial in providing cost-efficient alternatives to Reinforced Concrete (RC) KJ structures in areas with low to moderate level of seismic risks.

Seismic response of reinforced concrete wall buildings with nonlinear coupling slabs

Reinforced concrete (RC) structural walls are widely used in high-rise buildings as the lateral force resisting system because of their inherent economy, stiffness, and strength. The floor plan configuration of residential buildings in Chile consists mainly in assemblies of large longitudinal walls and shorter transverse walls coupled by floor slabs. The coupling effect of the slabs has affected the response and the observed damage of RC buildings in recent earthquakes. The main objective of this article is to assess the seismic response of a RC structural wall building with coupling slabs. Additionally, the effect of the amount of slab reinforcement on the seismic response of the building is evaluated. To achieve the proposed objectives, seven three-dimensional models of a case study building were developed using shell-type elements in DIANA. The first four models aim to evaluate the effect of using elastic slabs with reduced (i.e. cracked) moment of inertia. The last three models consider nonlinear behavior for both walls and slabs. The response of the building was estimated using nonlinear static analysis and the seismic performance is evaluated from the results of roof displacement and shear, moment, and axial forces of the walls. Additionally, the seismic performance is evaluated from the strain demands of concrete and steel in both walls and slabs. Relevant conclusions about the building behavior, slab demands, and failure mode are drawn.

Using composite yield mechanism to mitigate seismic damage to exposed steel column base connections

A novel exposed column base (ECB) connection, featuring composite yield mechanism (i.e., a combination of anchor rod and base plate yielding), has been recently proposed in Japan for optimum seismic performance. This paper focused on investigating the effects of using composite yield mechanism on damage mitigation for ECB connections. In doing so, four two-thirds scale specimens, with different base connection configurations, were tested under combined flexure and axial load. Their performances were assessed and compared in terms of damage evolution, moment-rotation relationship and energy dissipation. The experimental results showed that for ECB connection with composite yield mechanism, both anchor rod and base plate will actively contribute to the moment resistance and energy dissipation. This can successfully postpone the interior anchor rod yielding and fracture, compared to the ECB connection with anchor rod yield mechanism. Meanwhile, the strain demands on exterior plate can be also released compared to the ECB connection with base plate yield mechanism. The relative contributions from anchor rod and base plate of ECB connection with composite yield mechanism can be controlled by changing the exterior plate thickness. In addition, an analytical method was proposed to predict the yield and ultimate moment strength for the Composite Yield ECB connection based on the principle of virtual work. The difference between predicted and measured moment strength is within 15%, showing the validity of the proposed method for moment strength prediction.

Strain demand prediction of buried steel pipeline at strike-slip fault crossings: A surrogate model approach

Significant progress in the oil and gas industry advances the application of pipeline into an intelligent era, which poses rigorous requirements on pipeline safety, reliability, and maintainability, especially when crossing seismic zones. In general, strike-slip faults are prone to induce large deformation leading to local buckling and global rupture eventually. To evaluate the performance and safety of pipelines in this situation, numerical simulations are proved to be a relatively accurate and reliable technique based on the built-in physical models and advanced grid technology. However, the computational cost is prohibitive, so one has to wait for a long time to attain a calculation result for complex large-scale pipelines. In this manuscript, an efficient and accurate surrogate model based on machine learning is proposed for strain demand prediction of buried X80 pipelines subjected to strike-slip faults. Specifically, the support vector regression model serves as a surrogate model to learn the high-dimensionally nonlinear relationship which maps multiple input variables, including pipe geometries, internal pressures, and strike-slip displacements, to output variables (namely tensile strains and compressive strains). The effectiveness and efficiency of the proposed method are validated by numerical studies considering different effects caused by structural sizes, internal pressure, and strike-slip movements.

Yeast Biodiversity in Fermented Doughs and Raw Cereal Matrices and the Study of Technological Traits of Selected Strains Isolated in Spain.

Bakers use pure microorganisms and/or traditional sourdoughs as the leavening agent for making bread. The performance of each starter and the substances produced by the microorganisms greatly affect the dough rheology and features of breads. Modern sourdoughs inoculated with selected lactic acid bacteria and yeasts are microbiologically stable, safer than traditional sourdoughs, and easy to use. However, the commercial repertoire of baker’s yeasts is still limited. Therefore, there is a demand for new strains of yeast species, capable of conferring distinctive traits to breads made from a variety of agri-food matrices, in the design of innovative starters. In this context, we report the first comprehensive study on yeasts isolated from a wide range of fermented doughs, cereal flours, and grains of Spain. Nine yeast species were identified from 433 isolates, which were distributed among separate clades. Moreover, phenotypic traits of potential technological relevance were identified in selected yeast strains. Mother doughs (MDs) showed the greatest yeast biodiversity, whereas commercial Saccharomyces starters or related and wild strains often dominated the bakery doughs. A metataxonomic analysis of wheat and tritordeum MDs revealed a greater richness of yeast species and percentage variations related to the consistency, flour type, and fermentation time of MDs.

Seismic performance evaluation of Cu-Al-Mn shape memory alloy concentrically braced frame

Cu-Al-Mn is one of the shape memory alloys (SMAs), which has been newly studied in recent years. This material can be used instead of typical Ni-Ti SMA since it can reduces material cost and dependence on temperature and loading rate, also, increases machinability and cold workability. In the present study, the seismic application of Cu-Al-Mn bars was evaluated as a part of the steel brace, selecting a 2D two-story split-X braced frame. FEMA P-695 methodology used to compare the collapse performance of two systems in the special concentrically braced frame (SCBF) and Cu-Al-Mn SMA braced frame (SMABF). Then the seismic response of the two systems was investigated at the different levels of earthquake intensity under nonlinear incremental dynamic analysis. The results showed that the SMABF had an allowable and more significant margin collapse compared to the SCBF system. The fragility curve of the two systems showed that the Cu-Al-Mn brace decreased the collapse probability of the frame. The collapse probability of Cu-Al-Mn brace was reduced by 82% and 45% at the maximum considered earthquake (MCE) and 1.5 times of MCE, respectively, compared to the collapse probability of the SCBF system. The SMABF had an allowable maximum inter-story drift ratio, having more distribution over the height of the frame in collapse point under all records but under 21% of records, the maximum inter-story drift ratio of the SCBF reached over 2.5%. The Cu-Al-Mn brace reduced the axial strain demand of the brace and inter-story drift of the 1st floor and residual drift. The result showed that the decreasing percentage of axial strain was 36% on average under the MCE intensity level of earthquakes. Also, the application of Cu-Al-Mn SMA in the braced frame increased the maximum top acceleration about 69% at the MCE level. Therefore, increasing acceleration in this system must be considered in the design of non-structural components. Despite the effectiveness of this new material, low ductility and poor energy dissipation were two weak points of this system. Therefore, this new alloy suggested using with other damping systems, or boundary frame with rigid connections to provide extra energy dissipation.

Load transfer between thin steel plates and ultra-high performance concrete through different types of shear connectors

The unique compressive and tensile characteristics of ultra-high performance concrete (UHPC) have enabled advancement of non-traditional shear connectors to provide composite action between UHPC and steel elements. The focus of the current technical literature in this area has been mainly on shear connectors that are used for the load transfer between flange plates and UHPC slabs. There remains a knowledge gap in the applicability of conventional and novel types of shear connectors to thin steel plates, such as web or stiffener plates. This knowledge is critical for the advancement of design guides for steel-UHPC composite members with fully embedded steel shapes and design guides for rehabilitation and reinforcement of the web plate of steel girders. This paper presents the experimental evaluation of three simple shear connectors: (1) traditional headed studs, (2) demountable threaded bars secured with nuts and (3) UHPC dowel connectors. The experimental results show that the connection is governed by fracture of the stud or threaded bar shank adjacent to the weld or at the interface between the web plate and the nut, respectively. The UHPC dowel connectors display brittle interface shear failure of the UHPC, followed by ductile pull-out behavior of the steel fibers. For large-diameter UHPC dowels, it was observed that yielding of the steel plate in bearing controls the capacity because of the relatively small thickness of the steel plate. The failure mechanisms, capacity and stiffness values, and strain demands on the embedded steel plates are presented and discussed. These experimental results are expected to broaden the knowledge of shear connectors incorporated into relatively thin plates and embedded in UHPC.

Reliability evaluation method for pipes buried in fault areas based on the probabilistic fault displacement hazard analysis

The tectonic fault poses a great threat to buried pipe segments. Buckling or rupture of pipes will ensue due to large strain induced by continuously increasing fault movements. In this study, a reliability-based methodology is conceptually proposed for designing new buried pipes or assessing existing pipes installed in fault areas. Uncertainties associated with the influencing factors of pipe structure and seismic loading (fault displacement) generated by earthquakes are considered. For pipe structural reliability, a developed back-propagation neural network (BPNN)-based surrogate model is utilized for the strain demand term in the limit state function for reliability calculations. Given statistical data for the basic variables including diameter, wall thickness, internal pressure, intersection angle or dip angle, and soil spring resistances, the conditional probability of failure can be obtained at a particular fault displacement by Monte Carlo simulation. Uncertainty of the fault displacement is estimated based on probabilistic fault displacement hazard analysis (PFDHA) having results given as probability of exceeding a certain fault displacement level for a specific site, then the occurrence probability of a specific fault displacement at a specific time can be indirectly obtained. The actual probability of failure (PoF) is calculated as an integral of fault displacement based on the total probability which is the product of the conditional PoF of pipe structure and occurrence probability of the specific fault displacement. This developed methodology is applied to a case study about a pipe project from China. Results show that the probability of failure increases with the elapsed time but stay within the safety margin for the next 30 years. Generally, the result of PFDHA is an essential input parameter in reliability analysis for pipes buried in fault regions. The multidisciplinary combination of structural reliability analysis and fault displacement hazard analysis is of practical significance for the reliability-based study of pipes in fault regions.