Design Of Civil Engineering Structures Research Articles

Seismic Performance Assessment and Enhancement Strategies for Civil Engineering Structures

Against the backdrop of rapid socio-economic development in our country and the accelerated pace of urbanization, the construction industry has been provided with a vast space for vigorous development. With the increasing demands for building quality, the design of civil engineering structures faces higher challenges and standards. Designers, in the design process, must not only pursue the aesthetic effect of buildings but also pay more attention to the safety of structures. Seismic design has received widespread attention in today's society, as its effectiveness is directly related to the stability and durability of building structures, which in turn affects the personal safety of building users. Therefore, in the design process of civil engineering structures, designers must establish advanced seismic design concepts, making seismic performance one of the core elements of design. To achieve this goal, designers need to scientifically and reasonably determine the seismic grade of buildings by combining multiple factors such as the geological conditions of the project location, history of seismic activity, and building usage. Meanwhile, advanced seismic technologies and materials need to be adopted to ensure that building structures can effectively absorb and disperse seismic energy during earthquakes, thereby maximally protecting the safety of buildings and their users.

Reliability analysis of bridges under different loads using polynomial chaos and subset simulation

AbstractReliability analysis of bridges is essential for the design of civil engineering structures. The classical methods, such as Monte Carlo Simulation (MCS) and subset simulation techniques, may provide accurate results. However, since the finite element model of the large‐scale civil engineering structures usually consists of a large number of degrees of freedom, structural reliability analysis of such structures is time‐consuming and computational intensive, which may restrict the use of these methods. This paper proposes a novel method for the reliability analysis of bridge under different types of loads by combining Polynomial Chaos (PC) and subset simulation techniques. The surrogate model of the limit state function is approximated by using the PC expansion, in which the PC coefficients are obtained from the least‐squares method. The subset simulation with a PC‐based surrogate model is then used to estimate the rare failure probability. Reliability analyses of bridge structures under different loading types, that is, static load, dynamic moving load, and seismic load are performed. Studies by using the MCS method and the classical subset simulation are also conducted, and the results from the proposed approach are compared with those from MCS and subset simulation to demonstrate the accuracy and efficiency of the proposed method.

Estimation of response reduction factor for Indian standard code designed reinforced concrete frames considering nonlinear soil-structure interaction effects

To incorporate the advantages of inelastic behaviour in design of civil engineering structures under seismic excitations, contemporary seismic design codes adopt a factor, termed as response reduction (or modification) factor (). This factor is considered to calculate the seismic demand of a structure by estimating the inelastic base shear from its linear counterpart. This study first evaluates the adequacy of R values provided in Indian seismic codes by performing numerical studies on different reinforced concrete (RC) frame buildings, which are designed following the provisions of contemporary Indian seismic codes. In particular, to assess the values of R for multi-storey RC frames, the present work utilises rigorous incremental dynamic analysis (IDA). Next, in order to understand the influence of flexible base conditions on R values, elastic and inelastic soil-structure interactions (SSI) are incorporated in the analysis. In flexible base condition, Type II (medium) and Type III (soft) soil conditions (as per Indian seismic code) are considered to characterise the base soil and for designing the isolated footings of the frame structures considered in this study. It has been observed from this study that for both fixed and flexible base conditions, the code specified R value may not be conservative in some cases.

Hybridization of Differential Evolution and Adaptive-NetworkBased Fuzzy Inference System in Estimation of Compression Coefficient of Plastic Clay Soil

One of the important geotechnical parameters required for designing of the civil engineering structure is the compressibility of the soil. In this study, the main purpose is to develop a novel hybrid Machine Learning (ML) model (ANFIS-DE), which used Differential Evolution (DE) algorithm to optimize the predictive capability of Adaptive-Network-based Fuzzy Inference System (ANFIS), for estimating soil Compression coefficient (Cc) from other geotechnical parameters namely Water Content, Void Ratio, Specific Gravity, Liquid Limit, Plastic Limit, Clay content and Depth of Soil Samples. Validation of the predictive capability of the novel model was carried out using statistical indices: Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Correlation Coefficient (R). In addition, two popular ML models namely Reduced Error Pruning Trees (REPTree) and Decision Stump (Dstump) were used for comparison. Results showed that the performance of the novel model ANFIS-DE is the best (R = 0.825, MAE = 0.064 and RMSE = 0.094) in comparison to other models such as REPTree (R = 0.7802, MAE = 0.068 and RMSE = 0.0988) and Dstump (R = 0.7325, MAE = 0.0785 and RMSE = 0.1036). Therefore, the ANFIS-DE model can be used as a promising tool for the correct and quick estimation of the soil Cc, which can be employed in the design and construction of civil engineering structures.

Geomorphology in environmental management 1965–2000

Abstract The period 1965–2000 saw the concept of applying geomorphology to a range of environmental and engineering problems become a more mainstream activity. The refinement and development of new techniques in mapping, remote sensing, and hazard and risk assessment allied to the increased use of quantitative methods of measurement and analysis enabled geomorphologists to provide data that were directly relevant to all aspects of infrastructure and general land-use planning, as well as many facets of the construction industry. One application that emerged was the need to compile geomorphological data as part of a process of collecting all Earth science information to underpin national, regional and local land-use planning. Understanding fluvial and coastal processes and landforms was important for river and shoreline management, where to this day there remain many conflicting land-use requirements and ongoing discussions over the nature, extent and suitability of any proposed mitigation measures. The other main application was in civil engineering, where geomorphologists worked alongside engineering geologists and geotechnical engineers in the collection and interpretation of ground information data to assist in natural hazard identification and quantifying the risks associated with them, as well as supporting safe and economic design of civil engineering structures.

Nano-SiO2 for efficiency of geotechnical properties of fine soils in mining and civil engineering

Taking into account the decreased number of available lands, the construction of structures on soft soil leads towards the development of soil stabilizing models. This study is aimed at studying the decrement of land resources available, and the design of civil engineering structures on soft soils that will develop the soil impact of nano-SiO2 in the use of clay soil with low liquid limit, in particular shear resistance and unconfined compression. A novel nano-soil stabilizer has been created in this investigation by use of nano-SiO2 activity and ultrafine features that have enabled cement-based stabilizers to increase their characteristics in broad application possibilities. This research aims to examine the influence on soil engineering, particularly the shear strength of clay soil with a low liquid limit to the effect of adding nano-SiO2. Nano-SiO2 has 3 different percentages combined with soil (i.e., 0.5, 0.7 percent by weight of the parent soil), A direct shear test was used to evaluate the shear strength of the specimen, and then the results were analyzed by Artificial Neural Network (ANN) to increase the accuracy of outcomes. Increased nano-SiO2 concentration was shown to lead to an increased internal friction angle and cohesiveness on clay soil. The optimal content for nano-SiO2 is 0.7%. ANN could accurately demonstrate the shear strength percentages in nano-SiO2 content.

Analysis of Measures to Strengthen the Safety of Civil Engineering Structure Design

This article analyzes the relevant content of the safety design of civil engineering structures. This paper studies the common problems in the safety design of civil engineering structures, including design methods to be optimized, relatively low training efforts, relatively poor innovation capabilities, more construction safety hazards, unreasonable internal force combination design, and low safety supervision. The author studied how to optimize structural design methods, how to strengthen personnel training, how to deal with system innovation, how to strictly control building conditions, how to optimize the design of internal forces, and how to strengthen safety supervision. The purpose of this article is to improve the level of civil engineering structural design and improve the construction quality of construction projects.

Partial factor for local buckling of welded box sections

The accurate consideration of the local (plate) buckling resistance and the determination of the effective width is highly important in the design of civil engineering structures. The current effective width calculation method provided by the EN 1993-1-5 is mainly developed for I-sections subjected to bending. Several previous studies proved that the current design rules can overestimate the plate buckling resistance especially in case of square box sections subjected to pure compression. The purpose of the current study is (1) to investigate the local buckling resistance of welded square box section columns loaded by pure compression and pure bending moment separately, (2) to investigate the applicability of the Winter curve for these worst cases and (3) to provide the necessary partial factor to the application of the Winter curve according to the safety requirements of Eurocode. Another aim of the current study is to investigate the differences between normal strength steel (NSS: S235 – S355) and high strength steel (HSS: S420 – S960) structures on the local buckling resistance. Deterministic and stochastic numerical and experimental research programs are conducted to investigate the effect of residual stresses and geometric imperfections on the local buckling resistance of welded square box sections and the necessary partial factor is determined.

Research on the development of BIM technology based on the application in the field of civil engineering

The compliance of civil engineering structural design is the fundamental condition that determines the subsequent safety and life of civil engineering buildings. At the present stage of civil engineering structural design, most of them are based on two-dimensional planar structural design, which is less expressive and covers a single amount of information, and it is difficult to play its proper value in the actual design and construction process due to certain limitations. In such a background, BIM technology was born and has been promoted and applied to some extent. Compared with the traditional design system, BIM technology can gather data processing, data caching and data sharing and other mechanisms, and is valued by major design companies. This paper introduces BIM and describes the current situation and frontier of structural engineering discipline, and takes the application of BIM technology in civil engineering structural design as the basic research point to explore its application in civil engineering structural design and its possible problems and measures to solve them.

Liquefaction study of soils in unified model and liquefaction potential evaluation of compacted sand

Owing to their specific sedimentary or weathering formation history, most soils confronted in civil engineering can be categorised into clayey and sandy soils. In view of the great mechanical difference, particularly the distinct liquefaction resistance, then precisely simulate the mechanical and liquefaction characteristics of different type soils become an important research issue in seismic design of civil engineering structures. Considering soil turns into overconsolidated state once experiences stress unloading, and which affects the mechanical and liquefaction characteristics in turn. Based on the classical Cam-clay model, with the introducing of subloading surface concept, the subloading surface Cam-clay model provide an unified constitutive model in the numerical simulation of different type soils. Based on the comprehensive parametric studies of state variables evolution and anti-liquefaction capability of soil conducted in this paper, we creatively unified the relationship between OCR and relative density of soil that widely adopted in the liquefaction resistance evaluation of sandy soil, and our test results shows high correlation between these two parameters. These findings provide a solid theoretic support and guidance for the dynamic compaction method that widely adopted in anti-liquefaction design.

Reliability of Shear-Box Tests Upon Soaking Process on the Sand Soil in Al-Najaf City

Accurate prediction of the soil shear strength parameters is essential in the reliable geotechnical design of civil engineering structures. This recent paper investigates the effect of the dry testing condition on the shear strength parameters of the sandy soil using the direct shear apparatus and compared with the saturated condition tests in previous researches on the same soil. The dry soil, usually above the water table, is the principal condition of the Al-Najaf city soil in Iraq. Samples are selected from the site of the University of Kufa, which represents the sandy soil of the city. For reliability purposes, the soil is exposed to different pre-soaking durations (one, two, and four weeks) then air-dried for shear tests. The main results revealed that the angle of internal friction (Φ) tested as a dry sample decreases about -6% up to two-weeks soaking then recovered upon four-week soaking about +6%. Compared to the saturated testing, there are increases in F between 6%-17% from saturated tests. Finally, it is recommended to aware in the selection of testing conditions for calculations of the angle of internal friction.

Study on Safety and Economy of Civil Engineering Structural Design Based on Computer Model

Computer modeling is a favorite tool for building engineers. As a new productive force, it lays a solid foundation for the future development of model design. It can use computer 3D technology to design and make physical models of buildings, simulating the effects of digital space design that cannot be achieved by hand. Generally speaking, the application of computer three - dimensional model design in structural design of civil engineering is very outstanding. Based on the summary of the calculation model design, this paper analyzes the safety and economy of the structure design of civil engineering.

Application-oriented fundamental research on concrete and reinforced concrete structures: selected findings from an Austro-Chinese research project

In this paper, the significance of application-oriented fundamental research on concrete and reinforced concrete structures for progress regarding practical applications to structural design is addressed based on four examples. They were treated in a joint research project of Vienna University of Technology and Tongji University. The first topic refers to sudden heating or cooling of concrete structures, the second one to high-dynamic strength of specimens made of cementitious materials, the third one to structural analysis of segmental tunnel rings used in mechanized tunneling, and the fourth one to serviceability and ultimate limit states of concrete hinges used in integral bridge construction. The first two topics deal with exceptional load cases. Results from the fundamental research call for improvements of state-of-the-art simulation approaches used in civil engineering design. The last two topics refer to reinforced concrete hinges used in mechanized tunneling and integral bridge construction, respectively. Integrative research has led to progress regarding the verification of serviceability and ultimate limit states. In all four examples, results from fundamental research are used to scrutinize state-of-the-art approaches used in practical structural design of civil engineering structures. This allows for identifying interesting directions for the future development of design guidelines and standards.

Current revision of the fundamental Eurocode for design of civil engineering structures

Представлен применяемый в настоящее время пересмотр основного Еврокода EN 1990 при проектировании зданий и сооружений гражданского строительства. Доработаны основные требования с учетом структурного сопротивления, эксплуатационной надежности и долговечности. Кроме того, включены положения, касающиеся прочности, устойчивости и пожарной безопасности. При соответствующем уровне надежности конструкции следует учитывать возможные причины сбоя и последствия, неприятие общественностью и затраты, связанные со снижением риска сбоя. Однако выбор относительно уровня надежности остается за национальным толкованием. Целевые показатели надежности указаны для годичного и 50-летнего исходного (базисного) периода, причем в окончательном проекте prEN 1990 года нет прямой ссылки на расчетный срок эксплуатации. Предлагается разделить последствия разрушения конструкции на пять категорий, однако без рекомендаций по целевым показателям надежности для самого низкого и самого высокого класса последствий. Дополнительное руководство по структурной устойчивости предлагается в приложении prEN 1990, Annex E. Структура должна иметь достаточный уровень надежности, чтобы не быть поврежденной в степени, несоразмерной первоначальной причине. Расчетный срок эксплуатации должен рассматриваться для зависящих от времени эксплуатационных структур. Конечные и предельные состояния работоспособности должны быть верифицированы для всех соответствующих проектов. Помимо широко используемого метода парциальных коэффициентов, который включает в себя базовый метод структурной верификации, даются дополнительные указания по применению нелинейных методов. Парциальные коэффициенты были заново откалиброваны для достижения более сбалансированного уровня надежности для конструкций из различных материалов и эффектов нагружения.

Linear and nonlinear site response analyses to determine dynamic soil properties of Kirikkale

In order to make reliable earthquake-resistant design of civil engineering structures, one of the most important considerations in a region with high seismicity is to pay attention to the local soil condition of regions. It is aimed in the current study at specifying dynamic soil characteristics of Kirikkale city center conducting the 1-D equivalent linear and non-linear site response analyses. Due to high vulnerability and seismicity of the city center of Kirikkale surrounded by active many faults, such as the North Anatolian Fault (NAF), the city of Kirikkale is classified as highly earthquake-prone city. The first effort to determine critical site response parameter is to perform the seismic hazard analyses of the region through the earthquake record catalogues. The moment magnitude of the city center is obtained as Mw=7.0 according to the recorded probability of exceedance of 10% in the last 50 years. Using the data from site tests, the 1-D equivalent linear (EL) and nonlinear site response analyses (NL) are performed with respect to the shear modulus reduction and damping ratio models proposed in literature. The important engineering parameters of the amplification ratio, predominant site period, peak ground acceleration (PGA) and spectral acceleration values are predicted. Except for the periods between the period of T=0.2-1.0 s, the results from the NL are obtained to be similar to the EL results. Lower spectral acceleration values are estimated in the locations of the city where the higher amplification ratio is attained or vice-versa. Construction of high-rise buildings with modal periods higher than T=1.0 s are obtained to be suitable for the city of Kirikkale. The buildings at the city center are recommended to be assessed with street survey rapid structural evaluation methods so as to mitigate seismic damages. The obtained contour maps in this study are estimated to be effective for visually characterizing the city in terms of the considered parameters.

Comparison of theoretical deformation with real life model of a steel bridge span

The article presents the selection process of a static system and optimization for steel bridge span. The issue was addressed as an entry to a BRICO 2017 contests in designing steel bridges. The proposed solutions were checked in terms of their bearing capacity, technological assembly and economics. General guidelines for geometry selection were described. The designed construction was produced and tested under load to determine the deflection in both vertical and horizontal plane. Furthermore, the article details the joints and technological issues met during the design process. Theoretical calculations and actual measurements on a real life model were compared. The process of structural design of civil engineering structures is a complicated, time consuming multilayered issue. The key to a good design lies in a compromise between esthetics, functionality, capacity exhaustion and technical possibilities.

A fuzzy residual strength based fatigue life prediction method

The fatigue damage problems are frequently encountered in the design of civil engineering structures. A realistic and accurate fatigue life prediction is quite essential to ensure the safety of engineering design. However, constructing a reliable fatigue life prediction model can be quite challenging. The use of traditional deterministic approach in predicting the fatigue life is sometimes too dangerous in the real practical designs as the method itself contains a wide range of uncertain factors. In this paper, a new fatigue life prediction method is going to be proposed where the residual strength is been utilized. Several cumulative damage models, capable of predicting the fatigue life of a structural element, are considered. Based on Miner\'s rule, a randomized approach is developed from a deterministic equation. The residual strength is used in a one to one transformation methodology which is used for the derivation of the fatigue life. To arrive at more robust results, fuzzy sets are introduced to model the parameter uncertainties. This leads to a convoluted fuzzy based fatigue life prediction model. The developed model is illustrated in an example analysis. The calculated results are compared with real experimental data. The applicability of this approach for a required reliability level is also discussed.

飽きのこない土木構造物の計画および設計に関する基礎的考察

飽きのこない土木構造物の計画および設計に関する基礎的考察

Strong Motion Observation from Recent Destructive Earthquakes in China Mainland

Strong earthquake motion observations have gathered much useful data for the seismic-resistant design of civil engineering structures, and for developing earthquake prevention technology. The performance of Chinese strong motion network has been evaluated from recent earthquakes in Chinese Mainland. To follow the new requirement of the earthquake mitigation plan, some new practice of strong motion observations are described, including rapid urban ShakeMap, earthquake early warning system.

Facility Management as Part of an Integrated Design of Civil Engineering Structures

Abstract The present article deals about facility management, as still relatively young component of an integrated planning and design of buildings. Attention is focused on the area of the proposal, which can greatly affect to amount of future operating costs. Operational efficiency has been divided into individual components and satisfaction with the solution of buildings already constructed was assessed by workers, who are actually dedicated facility management in these organizations. The results were then assessed and evaluated through regression analysis. The aim of this paper is to determine to what extent is desired update project documentation of new buildings from the perspective of facility management.