Siwei Liu

Siwei Liu
The Hong Kong Polytechnic University | PolyU · Department of Civil and Environmental Engineering

PhD in Structural Engineering

About

58
Publications
5,204
Reads
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508
Citations
Citations since 2016
46 Research Items
468 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Additional affiliations
January 2022 - September 2022
The Hong Kong Polytechnic University
Position
  • Professor (Assistant)

Publications

Publications (58)
Article
This is the part two of the two companion papers, which extends the element formulations and the applications of the curved ALH (Arbitrarily Located Hinge) element to three-dimensional space for direct analysis of the steel frames considering large deflection and inelastic behaviors. A simplified approach assuming the space frame to deform with fin...
Article
A new and advanced beam-column element, namely the curved tapered-three-hinges (TTH) beam-column element, is proposed in this paper. The present element can perform large deformation analysis and explicitly simulate the initial member curvature, which is essential for the second-order direct analysis using one-element-per-member models. Another dis...
Article
Hybrid frames composed of steel, concrete and composite members are widely used to-date due to their structural efficiency and economy as alternatives to traditional bare steel system, especially in high-rise buildings. However, the present design of this structural form is both inconvenient and inconsistent as it needs several separated design cod...
Article
Robust geometric and material nonlinear analysis of buildings under ultimate loads is a key to success of advanced analysis, performance-based seismic design and progressive collapse analysis. This is the second part of two companion papers about the advanced analysis of hybrid steel and concrete frames allowing for various effects such as initial...
Thesis
Hybrid steel and concrete framed structures, which consist of bare steel (BS), reinforced concrete (RC) and steel-concrete composite (SCC) members, are more increasingly and extensively used in modern buildings. The structural benefit of this system is to combine the advantages of two construction materials with concrete having high compression str...
Article
With advancements in manufacturing technology, steel members can be innovatively fabricated in nonsymmetric section shapes and tapered along the length to bring certain benefits in material utilization and aesthetic appearance. The frame analysis of the steel structures with these members is quite challenging because of lacking the suitable line-el...
Article
The large diameter piles (LDP) are designed to provide strong bearing capacity, which should be carefully analysed to ensure the superstructures' reliability. The conventional discrete spring element (DSE) method with the Euler-Bernoulli beam element is inappropriate for LDPs as the pile's shear deformations may be considerable. Besides, the nonlin...
Article
Full-text available
Submarine pipeline is used for transporting oil from wells to resource storage facilities. The oil inside the pipeline is heated and pressured for long-distance transportation, making the pipeline under high temperature and high pressure (HTHP). The pipeline is usually placed inside a trench where surrounding soil restraints its longitudinal expans...
Article
Deterioration of offshore steel sheet pile walls subjected to corrosion may significantly affect the structural performance under serviceability and failure. Most steel corrosion studies focused on the mechanism of reflecting the actual corrosion situations to establish a relatively realistic corrosion model. The mechanical performances of the mate...
Conference Paper
With the advancement in manufacturing technology, fabricating nonsymmetric steel sections by cold-forming or robotic welding is feasible, enabling innovative structural forms of being more structurally efficient. Nevertheless, members with nonsymmetric sections usually experience complex behaviour such as torsional, flexural-torsional, and lateral-...
Article
The warping effects may predominate in geometrically nonlinear analysis of open cross-section members. The formulation of conventional beam-column elements incorporating the warping effects is cumbersome due to the method considering the inconsistency between the shear center and centroid. To develop a concise warping element formulation, this pape...
Article
Geometric and material nonlinear analysis Nonsymmetric cross-sections Steel Numerical analysis Tangent stiffness matrix Modified tangent modulus approach A B S T R A C T Steel members using nonsymmetric sections are often used for their structural efficiency in contemporary construction. Notwithstanding, the conventional concentrated plasticity (CP...
Article
The Morgenstern-Price (MP) method is an effective solution to compute the factor of safety (FOS) of a slope against sliding that has been used extensively for decades. In the MP method, the soil mass above the slip surface needs to be tediously divided into vertical slices to compute the force and moment integrals. The proposed research improves th...
Article
This paper developed an efficient algorithm to study the elastic buckling strengths of non-uniformly corroded steel members. The algorithm is derived based on the authors' previous work on buckling strength assessment for the steel members by further introducing random non-uniform corrosion damage to the cross-section along member. In the algorithm...
Article
Monte Carlo simulation has been widely used to deal with random problems. Corrosion of steel structures is of high random nature. Current studies on the behavior of steel structures considering corrosion effect are usually executed by using the commercial finite element analysis software, which costs huge computational time to ensure sufficient Mon...
Article
Tapered I-section steel members can achieve efficient material utilization, and are economical alternatives to traditional prismatic ones. Current line-element formulations for tapered I-section members may not accurately capture buckling behavior because they typically ignore shear and warping deformations. The research refines the existing line-e...
Article
Tapered piles have superior benefits over traditional cylindrical piles in resisting axial and lateral loads, being an economical alternative to cylindrical piles. When designing the tapered pile in soft or liquefiable soil, it is necessary to identify its buckling strengths. Notwithstanding, the buckling analysis of tapered piles considering nonli...
Article
The beam-column element analysis method has been extensively adopted in practice, relying on the robustness of its element formulation. Steel members with open sections are commonly used; their cross-sectional shapes are usually nonsymmetric to improve material efficiency. Nevertheless, an offset exists between the shear center and the centroid of...
Article
Piles are sometimes unavoidably embedded in slopes for supporting buildings on hills. In contrast to a pile on a horizontal ground, a pile in slope is acted on by additional sliding force from the slope, impairing its load-bearing capacity and buckling resistance. Nevertheless, proper assessment for the buckling of piles in slopes is difficult beca...
Article
Due to the complicated geological conditions and complex loads, the pile-soil interaction is a three-dimensional (3D) and highly nonlinear problem. Conventional numerical models have deficiencies to model the nonlinear soil-structure interaction (SSI) responses. This paper developed a 3D pile element model, which is capable of robustly simulating t...
Article
Thin-walled perforated singly symmetric open-section columns and braces are commonly used in industrial storage rack structures. They are difficult to analyze accurately because the shear center and centroid do not coincide and the complex buckling modes are involved. This paper explores the application of the newly extended MASTAN2-v5 program to a...
Article
An accurate structural analysis is a fundamental requirement for modern design. Nevertheless, this is often difficult for systems comprised of thin-walled members, mostly because of their complicated cross-section shapes with non-coincidence of shear center and centroid, and complex buckling modes. Recent research, using efficient line-finite-eleme...
Article
Full-text available
Subsea pipeline is the critical component in the offshore systems for transporting oil and gas from resource sites to ports. Its structural failure will be a disaster of heavily polluting the environment leading to unpredictable losses. The mediums inside subsea pipelines are conventionally heated in service for easier transporting after increasing...
Article
Driven Steel H-piles are commonly used in the deep foundation of being cost-effective and easy in workmanship. The post-driving residual stresses acting on the pile could be large when being driven in cohesionless sands, significantly affecting its compressive strength. Current design methods, mostly based on the empirical assumptions of using safe...
Article
A R T I C L E H I S T O R Y Comparing to other supporting pile walls, steel sheet piles with a lower flexural rigidity have a more obvious and significant second-order effect with the large deformation. Also, the nonlinear Soil-Structure Interaction (SSI) can highly influence the efficiency and accuracy of the deformation and buckling of the steel...
Conference Paper
The finite-element analysis method implementing line-elements is extensively adopted for the analysis and design of large-scale structures. The robustness of the element derivations and formulations decidedly impact the accuracy of capturing the actual member behaviors, thereby the structure deformations. This paper develops a new and innovative be...
Article
Tapered members produced by robotic fabrication techniques offer architectural and structural advantages and have the potential to become more prevalent than prismatic members. However, the conventional analysis and design methods based on simplified assumptions such as equivalent stiffness cannot be used to accurately evaluate a member's performan...
Article
The main objective of this paper is to validate a finite-element (FE) modelling protocol to simulate thin-walled members for static and dynamic analyses. Arbitrary-shaped cross-sections, including open, closed, and multicellular sections can be efficiently modelled for further advanced study. The framework is thoroughly validated and verified using...
Article
Pile serves as an essential component for transferring loads from superstructures to the soil ground. Proper consideration of soil-structure interaction (SSI) responses is crucial in evaluating the pile capacity and deflections under external loads. In the current design practices, semi-empirical or linear-elastic analyses are utilized, which are o...
Article
Modern structural design requires the nonlinear characteristics within structural behaviors to be considered in analysis. Due to the limited deformation capacity of the conventional cubic Hermite beam-column element, a frame member has to be finely meshed into a number of the beam-column elements for nonlinear analysis, leading to a huge computatio...
Article
Slender single piles are extensively used but susceptible to buckling when embedded in soft ground mediums. Owing to the complexity of soil properties, the soil-structure interaction (SSI) response is sometimes very complicated, but its consideration is essential in the design of slender piles. Current design practice relies on either empirical-bas...
Article
Open-sections are often used in structural applications because of their material efficiency in providing members of high strength and stiffness. Although previous research has made significant progress in accounting for the effects when the shear-center and centroid are not coincident for such sections, the compression buckling strengths of non-sy...
Article
Conventional steel-plates-strengthened-composite ring (SPSC) joints are extensively used in composite structures to connect concrete-filled tubular (CFT) columns and reinforced concrete (RC) beams. However, the refinancing-bars of the adjacent beams require on-site welding to the steel strengthened plates of the SPSC joint, which, regarding workman...
Article
Steel tapered-I-columns are popular in modern buildings due to its material efficiency and the convenience in construction. For evaluating the flexural buckling strength of these columns, the current design methods with empirical and idealized assumptions are sometimes unreliable, especially for slender columns with significant tapering ratios. To...
Article
In the structural stability design using direct analysis method (DM), the member initial geometric imperfections should be explicitly simulated. In current design practices, the imperfection shape is usually assumed as a half-sinusoidal curve. For the design of tapered columns, however, the use of this initial configuration may overestimate the buc...
Article
Non-prismatic members are popular for civil engineering structures. This paper derives a set of unified beam-column formulations for nonlinear static and dynamic analyses of the structures made of members with tapered sections, addressing the problems in engineering design practices. The element shape-functions are established upon the local-axes b...
Article
Non-symmetric thin-walled open-sections are used extensively in metal structures. The behaviour of such sections is usually complex because their shear centre and centroid do not coincide, and as a result, they are often susceptible to lateral-torsional and/or flexural-torsional buckling. This paper develops an efficient and robust computational fr...
Conference Paper
Full-text available
Mild steel hot-rolled sections are commonly prismatic because of the rolling process with a furnace, but welded sections made from steel plates do not have such a constraint, especially when robotic welding machines are used. The weight saving could be very significant by, say, using wide flanged section at mid-span and a small flanged section at e...
Article
Low-cost robotic welding and wide availability of high strength steel plates of grades over 500MPa make the use of tapered members an economical alternative to conventional prismatic members for modern steel structures, as experienced by the authors in some practical projects in Hong Kong and Macau. This paper proposes a new and efficient numerical...
Chapter
Use of columns fabricated from high-strength steel (HSS) plates with design strength larger than 460 MPa is becoming popular in congested cities like New York, Hong Kong and Shanghai and so on. The column sizes using high strength material can be considerably reduced, so the usable floor area is increased. Also, load from structural weight at const...
Article
A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is...
Article
Moment-thrust-curvatures (M-P-Φ curves) are fundamental quantities for detailed descriptions of basic properties such as stiffness and strength of a section under axial loads required for accurate computation of the deformations of reinforced concrete or composite columns. Currently, the finite-element-based methods adopting small fibers for analyz...
Article
This paper proposes an efficient numerical analysis technique for static and dynamic analysis of space steel frames by one-element-per-member model, considering material and geometric nonlinearities including P-Δ-δ effects, large global deflections and member deformations. The curved arbitrarily-located-hinge (ALH) beam-column element is developed...
Article
Members with tapered sections are popularly used in contemporary structures for architectonic appearance, besides that, this is in the most optimal, economic and effective manner to use material to the actual requirement according to the section strength along the member length. This paper proposes a new design approach based on direct analysis met...
Article
High-strength-concrete (HSC) is brittle, but its ductility can be dramatically increased when confined by steel tubes. However, the size of hot-rolled tubular sections is commonly limited to 600 mm, its capacity as mega columns in many high-rise buildings is inadequate. This paper details the use of fabricated and rolled sections as mega-columns by...
Article
The terms “Second-order Analysis” and “Direct Analysis” appear in many modern design codes but many engineers consider this as a method for checking only the second-order sway effect, nonlinear sway moment or a tool for academic research. This perception is incorrect in modern structural design and in fact this old approach is defined only as the s...
Article
Prediction of the column strength, associated with buckling and material yielding, is vital in a successful design. In this paper, a completely numerical analysis technique is employed for simulating the compressive behavior of Q690 high-strength steel columns with box- and H-sections, and its accuracy is verified by the experimental results as pre...
Article
This paper proposes an efficient numerical simulation technique for dynamic time-history analysis of space steel frames by one-element-per-member model, considering geometric nonlinearity including P-Δ-δ effects, large global deflections and member deformations. The curved arbitrarily-located-hinge (ALH) beam-column element is employed for capturin...
Article
Certain benefits in terms of the efficiency in material consumption can be achieved by adopting tapered steel members in long-span structures. In this paper, analytical solutions for second-order analysis of non-prismatic steel members by a series of tapered beam-column elements are firstly proposed. The exact stiffness matrices for five common typ...
Article
This paper proposes a direct analysis method (DAM) for design of high-strength steel members and frames allowing explicit modeling of residual stresses. A section analysis technique, based on quasi-Newton iterative scheme, is employed taking into account for the effects of residual stress. Two distributed patterns of residual stress for the welded...
Article
This paper, as the first part of the two companion papers, proposes a new and curved beam-column element with arbitrarily-located plastic hinge for second-order inelastic or direct analysis of planar steel frames. Unlike the conventional plastic hinge element which requires two and more elements to capture the locations of plastic hinge along membe...
Article
Structures composed of concrete-filled steel hollow sections are widely used to-date due to their structural efficiency and economy. This paper proposes a second-order design method which requires only section capacity check without need of assuming an effective length and using prescriptive formulae in different codes and the shape of the member c...
Article
Full-text available
Before the publication of several new codes for structural design of steel structures in recent years, design of structures is based on the linear analysis and the effective length method, which relies on a nonexistent or erroneous assumption of buckling at undeformed geometry. After the publication of the several codes including the Eurocode-3 (20...
Article
Nonlinear static (pushover) analysis is an effective and simple tool for evaluating the seismic response of structures and offers an attractive choice for the performance-based design. As such, it has generally been used in modern design due to its practicality. However, the nonlinear plastic design method consumes extensive computational effort fo...

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Projects

Projects (6)
Project
To devleop efficient elements for practical application.
Project
To develop direct analysis method for steel structures.
Project
To establish the modern structural design method for tapered sections.