Type Of Structural System Research Articles

Rapid Seismic Vulnerability Assessment of Low- to Mid-Rise Reinforced Concrete Buildings Using Bingöl's Regional Data

A methodology based on multiple linear regression analysis is used for rapid vulnerability assessment of a building set surveyed in the disaster area of the 1 May 2003 Bingöl, Turkey, earthquake. The data set represents the population of low- to mid-rise reinforced concrete buildings in Bingöl. In addition to the relevant statistical procedures for parameter selection, all possible regressions of selected building parameters are carried out, and the most appropriate regression function is determined. Structural system type, newly introduced span index, priority index, existence of captive columns, and soft story index are found to play the dominant role. A leave-one-out cross validation method is utilized to test the reliability of derived regression function. The data collected during 1999 Düzce earthquake is also used for testing. The correct classification rate for both calibration and test data is found to be near 90%, despite an acceptable increase in incorrect classification rate.

Horizontal Skyscraper: Innovative Structural Design of Shenzhen VANKE Center

The Shenzhen VANKE Center included both the required ground clearance to the first floor of 10–15 m as well as unsupported spans in excess of 50 m. The concept of building on cable-stayed bridges was finally selected. In this design, a system consisting of inclined prestressed cables and rigid composite floor systems is used to transfer the gravity loads from the superstructure to the tubes, walls, and columns. The simulation of the construction sequence of the cable prestressing and the structural behaviors are revealed. The innovative structural concept and design methods could be used as a reference. Long-span buildings are usually associated with specialpurpose structures (stadiums, airports, etc.), and the type of structural systems that consequently have evolved can be viewed as an extension of the concepts used in the construction of domes and arches. Until now, the conventional design of typical long-span office and mixed-use buildings has involved the use of transfer structures to support the main superstructure, such as in the incorporation of megatrusses, in which the height can exceed that of a single story. These transfer truss systems also provide additional lateral stiffness to the overall structure. The challenges posed by the architectural design of the Shenzhen VANKE Center included both the required ground clearance to the first floor of 10–15 m as well as that required for unsupported spans in excess of 50 m. Following a comparison of several structural schemes, the concept of building on cable-stayed bridges was finally selected. Moreover, after considering the architectural specifications and the requirements of the surrounding space, it was evident that anchoring cables could not be utilized in the proposed cable-stayed building scheme. Therefore, in this design, a system consisting of inclined prestressed cables and rigid composite floor systems was used to transfer the gravity loads from the superstructure to the tubes, walls, and columns. Four innovative concepts were introduced in the realization of the project: (1) techniques for preventing slack in the cables; (2) precise adjustment of prestressing forces in the cables; (3) self-balanced structural design and construction; and (4) control of lateral displacements during construction of the structure. The details of these concepts as well as the construction sequence of the cable prestressing and critical aspects of the structural system are presented in this paper.

Shear Resistant Strength Analysis of Construction Formwork Concrete Shear Wall

Construction formwork concrete shear wall is one of new type of structural system. In order to study the shear resistant strength of construction formwork concrete shear wall, 21 quasi-static test results were collected, influence factors which affect the shear resistant strength of construction formwork concrete shear wall through grey-correlation analysis method were analyzed. It is found that, among the influence factors, axial compressive force is the most important, secondly is the effective height of the wall, the distance among stiffening ribs in the latitudinal direction show small influence. And the expressions to estimate the shear resistant strength of construction formwork concrete shear wall were proposed by regression analysis method.

Accuracy of combination rules and individual effect correlation: MDOF vs SDOF systems

The accuracy of the 30% and SRSS rules, commonly used to estimate the combined response of structures, and some related issues, are studied. For complex systems and earthquake loading, the principal components give the maximum seismic response. Both rules underestimate the axial load by about 10% and the COV of the underestimation is about 20%. Both rules overestimate the base shear by about 10%. The uncertainty in the estimation is much larger for axial load than for base shear, and, for axial load, it is much larger for inelastic than for elastic behavior. The effect of individual components may be highly correlated, not only for normal components, but also for totally uncorrelated components. The rules are not always inaccurate for large values of correlation coefficients of the individual effects, and small values of such coefficients are not always related to an accurate estimation of the response. Only for perfectly uncorrelated harmonic excitations and elastic analysis of SDOF systems, the individual effects of the components are uncorrelated and the rules accurately estimate the combined response. In the general case, the level of underestimation or overestimation depends on the degree of correlation of the components, the type of structural system, the response parameter, the location of the structural member and the level of structural deformation. The codes should be more specific regarding the application of these rules. If the percentage rule is used for MDOF systems and earthquake loading, at least a value of 45% should be used for the combination factor.

Light Gauge Steel-Light Weight Aggregate Concrete Structure and Application

Light gauge steel-light weight aggregate concrete structure is a new type of structure system. This paper introduces the composition, characteristics and production and installation process of this kind of structure. For the Da Yunhe villas, as an example, this paper presents the structure detail and analysis method, and gives the bearing capacity and rigidity calculation result of the typical wall and floor beams, which verify the design code of the steel structure. This paper provides the beneficial reference and basis for future research and promotion.

Experimental Research on Seismic Performance of Cast-<i>In Situ</i> RC Grillage Shear Walls Formed with Heat Preservation Hollow Blocks

As a new type of structural system, the cast-in-situ reinforced concrete grillage shear wall system has functions of formwork, strength and heat preservation at the same time. It is suitable for residential buildings in seismic and non-seismic areas. The results of quasi-static tests on 20 specimens of small and large grid size grillage shear walls with different shear span ratios show that: both of small and large grid size grillage shear walls have excellent seismic performance; shear or bending deformation of horizontal and vertical limbs dissipate seismic energy so the elastic-plastic deformability of grillage shear walls meet the requirements of shear wall structure under strong earthquakes; the bearing capacity of grillage shear wall was calculated with formulas used for solid RC shear walls. The equivalent thickness of grillage shear wall equalized as solid shear wall is determined by elastic finite element analysis.

Study on Equivalent Damping Ratio of Shenzhen Baoan International Airport T3 Terminal

Today, the structures constituted by different materials, increase more and more, especially the lower part is concrete, the upper is steel. For this type of structural system, modal damping matrix is non-diagonal matrix, the earthquake response equation is coupled on the modal damping matrix, the modal coupling of the non-proportional damping system leads to the traditional real modal analysis methods not be directly applied. For such structure, the changes of the damping ratio are analyzed in this article. Finally, the equivalent damping ratio of Shenzhen Airport is obtained using the energy theory.

Study on Equivalent Damping Ratio of Shenzhen Baoan International Airport T3 Terminal

Today, the structures constituted by different materials, increase more and more, especially the lower part is concrete, the upper is steel. For this type of structural system, modal damping matrix is non-diagonal matrix, the earthquake response equation is coupled on the modal damping matrix, the modal coupling of the non-proportional damping system leads to the traditional real modal analysis methods not be directly applied. For such structure, the changes of the damping ratio are analyzed in this article. Finally, the equivalent damping ratio of Shenzhen Airport is obtained using the energy theory.

The Study on Seismic Reliability of CS Panel Structure

CS Panel Residential Structure is a new type of structural system investigated and manufactured for the requirements of wall reformation and residential industrialization.Now set up two finite element models on the basis of the two types of three storeys CS panel structure experimental models (including tectonic columns or not ) with the ratio 1:2.8 that designed before. Then analyze the random seismic response of the two types of CS panel structure under the action of ground motion acceleration power spectrum using the spectrum analysis module of the finite element analysis software ANSYS.Based on the first excursion failure theory and stochastic vibration theory, dynamic reliability of the CS panel structure subject to different seismic intensity is calculated and compared, the effect of the edge component is summarized using structure seismic response of random statistic.

Lattice Light Steel Frame System and Application

Lattice light steel frame is a new type of structural system, combining general steel framework which is composed of lattice column and lattice beam with lattice light steel keel of the partitions and floors, the system takes full advantages of both structural systems, with high speed construction, less steel consumption, good earthquake-resistance etc., and possesses good prospects. The paper describes the system construction approach and the characteristics of lattice light steel frame system, and provides a project example of a villa. The design method and calculation model of the project are presented. Calculation results meet the specifications’ requirements, proving the new system can be applied to practical engineering. The paper gives guidance for application and research of this new system.

Acoustic emission monitoring of composite containment systems

This paper considers two different types of composite containment system, and two different types of acoustic emission (AE) monitoring approach. The first system is a composite reinforced pressure vessel (CRPV) which is monitored both during construction and in-service using a broadband modal acoustic emission (MAE) technique. The second system is a membrane cargo containment system which is monitored using both a global as well as a local AE technique. For the CRPV, the damage assessment is concerned mainly with the integrity of the composite outer layer at the construction stage, and possible fatigue cracking of the inner steel liner at the in-service stage. For the membrane tank, the damage assessment is concerned with locating and quantifying any abnormal porosities that might develop in-service. By comparing and contrasting the different types of structural system and different monitoring approaches inferences are drawn as to what role AE monitoring could take in the damage assessment of other types of composite containment system. (Detailed technical data have not been included, due to client confidentiality constraints.)

Risk Analysis of Fatigue-Induced Sequential Failures by Branch-and-Bound Method Employing System Reliability Bounds

Various types of structural systems are often subjected to the risk of fatigue-induced failures. If a structure does not have an adequate level of structural redundancy, local failures may initiate sequential failures and cause exceedingly large damage. For the risk-informed design and maintenance of such structural systems, it is thus essential to quantify the risk of fatigue-induced sequential failure. However, such risk analysis is often computationally intractable because one needs to explore innumerable failure sequences, each of which demands component and system reliability analyses in conjunction with structural analyses to account for various uncertainties and the effect of load redistributions. To overcome this computational challenge, many research efforts have been made to identify critical failure sequences with the highest likelihood and to quantify the overall risk by system reliability analysis based on the identified sequences. One of the most widely used approaches is the so-called “bran...

Mechanics Characteristics Study for Cable-Stayed-Suspension Bridges

As a composite structure, the cable-stayed-suspension bridge is characterized by relatively new structure, great overall stiffness and long-span capacity, which has been proposed for the design of some extra long-span bridges. In order to research further into the mechanics characteristics of this type of structural system, the proposed preliminary design of a cable-stayed-suspension bridge with a main span of 1800m is analyzed by means of finite element simulation method. The advantages on overall stiffness in the cable-stayed-suspension bridge are summarized in comparison with the three-span suspension bridge and the single-span suspension bridge. Then, the reasons for the fatigue of the longest suspension cables in the cable-stayed-suspension bridge are also discussed in this paper.

Dynamic reduction-based structural damage detection of transmission towers: Practical issues and experimental verification

Structural damage detection in large-scale three-dimensional spatial structures is a challenging problem. It is impractical to develop a general damage-detection method that is applicable to all types of structural systems and all kinds of damage. A practical and efficient structural damage detection method must consider the characteristics of the target structure and damage in the development stage. In 2009, Yin et al. [33] proposed a damage detection method for the health monitoring of transmission towers. The method was developed based on the dynamical finite element (FE) model reduction technique, which utilizes identified modal parameters, such as natural frequencies and mode shapes, with only a limited number of sensors. In Ref. [33], the proposed method was numerically verified by simulated noisy data from a three-dimensional transmission tower model for single and multiple damage cases. This paper discusses some practical issues related to the proposed method, such as sensor placement and computational efficiency. Rather than proposing a general sensor placement method, a set of preliminary sensor locations is determined based on engineering judgement. This set of sensor locations is then checked against the results of a sensitivity analysis to ensure that the measured data contain information for identifying all of the target damage scenarios. To reduce the required computational power, two simplified versions of the proposed method are presented. The proposed method is then verified with a scaled-down model of a transmission tower (2.4 m high) that was built at the Structural Vibration Laboratory (SVL) of the City University of Hong Kong. This paper reports the detailed experimental setup and the method of extracting the modal parameters from a series of free vibration tests with only a limited number of sensors. The verification results show that the proposed damage detection method identifies the damaged sub-structures in all of the experimental cases considered. It must be pointed out that the transmission tower structure, in its operating conditions, suffers from the effect of the forces transmitted from the cables it carries. The influence of this force on the damage identification result is great and can not be neglected in practice. In the present experimental case study, only a transmission tower-like structure without carrying the cables is investigated in laboratory conditions.

Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Pre-tensioned high strength trusses using alloy steel bar are widely used as glass wall supporting systems because of the high degree of transparency. The breakage of glass panes in this type of system occurs occasionally, likely to be due to error in design and analysis in addition to other factors like glass impurity and stress concentration around opening in a spider system. Most design does not consider the flexibility of supports from finite stiffness of supporting steel or reinforced concrete beams. The resistance of lateral wind pressure of the system makes use of high tension force coupled with the large deflection effect, both of which are affected by many parameters not generally considered in conventional structures. In the design, one must therefore give a careful consideration on various effects, such as support settlement due to live loads and material creep, temperature change, pre-tension force, and wind pressure. It is not uncommon to see many similar glass wall systems fail in the wind load test chambers under a design wind speed. This paper presents a rigorous analysis and design of this type of structural systems used in a project in Hong Kong, China. The stability function with initial curvature is used in place of the cubic function, which is only accurate for linear analysis. The considerations and analysis techniques are believed to be of value to engineers involved in the design of the structural systems behaving nonlinearly.

SECOND-ORDER ANALYSIS FOR DESIGN OF GLASS-SUPPORTING AND PRE-TENSIONED TRUSSES

Glass wall supporting systems, comprising of pre-tensioned high strength trusses made from alloy steel bars, behave nonlinearly under wind and other loads. For a proper analysis and design, second-order and large deflection analyses are mandatory as the structural response like stress and deflections are highly dependent on the small movements and temperature effects. Also, careful consideration must be given to various effects such as support settlement due to live loads and material creep, temperature change, pre-tension force and wind pressure. It is not uncommon to see many glass wall systems fail in a simulated wind load test under the simulated design wind speed. This paper presents a rigorous analysis and design of this type of structural systems used in two projects in Hong Kong. The key message is the need to use "section strength check" in place of the member design adopted in the conventional effective length method for design of practical structures behaving nonlinearly since the prescriptive buckling check formulae become inaccurate or even invalid. The use of stability function allowing for initial imperfections in place of cubic Hermite element is proposed here because of the high degree of nonlinearity.

Middle-Story Isolated Structural System of High-Rise Building

For buildings of normal earthquake-resistant construction, it is essential to provide their structural frame with sufficient rigidity and strength horizontally and vertically, ensuring a uniform distribution of rigidity and strength in the plane. To this end, it is typical that those buildings adopt the same type of construction and structural system. On the other hand, in buildings of general base-isolation construction, their upper structure, which is supported by a base isolation layer, undergoes lessened seismic forces and therefore is able to tolerate concentration of rigidity and strength. This makes them available for construction with any types of structural systems, which in turn allows new structural planning realizing a greater freedom in architectural design; the same type of construction and structural system for the upper structure is generally adopted. In contrast, when a high-rise building is provided with an isolation layer in an intermediate level, its upper structure, which is placed above the isolation layer, has high seismic resistance as a seismic isolation structure. And a mass damper effect contributes to decrease in seismic responses in the lower structure, ensuring high seismic resistance of a building. This paper describes the physical properties of a seismic isolation layer system which is built at an middle-story of a building. It also introduce buildings by which potentials for new architectural planning are proposed through the use of this system.

Seismic Overstrength in Braced Frames of Modular Steel Buildings

The seismic behavior factor, R, is a critical parameter in contemporary seismic design. In the 2005 edition of the National Building Code of Canada, the R factor consists of ductility related force modification factor, Rd, and overstrength-related force modification factor, Ro. The choice of these factors for design depends on the structural system type. In this investigation, typical braced frames of Modular Steel Buildings (MSBs) are designed and modeled. Nonlinear static pushover analyses are conducted to study the inelastic behavior of these frames. Structural overstrength resulting from redistribution of internal forces in the inelastic range, design assumptions, and strain hardening behavior of steel and displacement ductility are evaluated and their relationships with some key response parameters are assessed. The results show that the reserve strength of MSB-braced systems is greater than that prescribed by the Canadian code for regular braced systems. It also appears that R depends on building height, contrary to what has been prescribed in many seismic design codes. It is concluded that some unique detailing requirements of MSBs need to be considered during design to eliminate undesirable seismic response.

Comparative study of structural material quantities of multi‐storey linear‐type residential buildings

AbstractOne of the main factors in the selection of the structural system for a multi‐storey linear‐type residential building is the initial construction cost of various structural systems. In many Asian countries, composite steel and concrete construction, and cast‐in‐place concrete framing construction are the most commonly used structural systems. However, there is insufficient data related to relative construction costs of these two structure types. In this paper, a representative floor plan was developed based on the examination of existing buildings of this type. A comparison of structural material quantities for representative building models up to 40 storeys in height using both types of structural systems was performed. Six models were developed based on a typical floor plan and were designed for gravity and lateral loadings. Quantities of materials for each model were calculated and compared in terms of each main structural material such as steel, concrete and reinforcement, and ratios of structural material quantities. The information presented can be utilized with appropriate cost data to compare estimates of initial construction costs of the two structural systems. Copyright © 2008 John Wiley & Sons, Ltd.

Dynamic behavior of tall buildings under wind: insights from full‐scale monitoring

AbstractThe wind‐induced response of tall buildings is inherently sensitive to structural dynamic properties like frequency and damping ratio. The latter parameter in particular is fraught with uncertainty in the design stage and may result in a built structure whose acceleration levels exceed design predictions. This reality has motivated the need to monitor tall buildings in full‐scale. This paper chronicles the authors' experiences in the analysis of full‐scale dynamic response data from tall buildings around the world, including full‐scale datasets from high rises in Boston, Chicago, and Seoul. In particular, this study focuses on the effects of coupling, beat phenomenon, amplitude dependence, and structural system type on dynamic properties, as well as correlating observed periods of vibration against finite element predictions. The findings suggest the need for time–frequency analyses to identify coalescing modes and the mechanisms spurring them. The study also highlighted the effect of this phenomenon on damping values, the overestimates that can result due to amplitude dependence, as well as the comparatively larger degree of energy dissipation experienced by buildings dominated by frame action. Copyright © 2007 John Wiley & Sons, Ltd.