Civil Engineering Sector Research Articles

Assessment of the Swelling Pressure of the Green Clay of Tangier (Morocco) Compared with the Soil-Moisture Conditions

The swelling phenomenon appears seriously when changing the soil-moisture conditions. The swelling pressure induced by the expansive soil can causes unfavourable problems or instability for the civil structures. So, understanding the soil behavior is considered a valuable work for engineers and consultants in the geotechnical and civil engineering sectors. In reality, the assessment of the swelling pressure of expansive soil depends, first of all, of test conditions related to the change of soil-moisture, as it happens, the influence of the combination “loading-start wetting” and also the unloading process after saturation. To this end, we establish an experimental study on the green clay of Tangier to evaluate the swelling pressure by using oedometer apparatus. Secondly, attention is bore to the combination “initial water content-dry density”, another factor related to the change of the soil-moisture, to show the influence of initial state condition on the swelling pressure.

A programme for continuing professional development of managers in the construction industry

The University of Stellenbosch construction management programme has been providing a four-week continuing professional development programme for construction managers since 1976. The programme is presented on an annual basis. It focuses on middle management in the construction industry which includes the building as well as civil engineering sectors of the industry. An overview of the present programme curriculum and curriculum development through the history of the programme is provided. Programme themes are selected to fit in with current management issues and topics. Key factors contributing to the success of the programme are also reviewed and analysed. The personal development and educational approach adopted as well as the philosophy of using a full immersion four-week residential course is discussed. The profile of types of delegates attending the programme is summarised. Programme faculty members are drawn from the major tertiary institutions in South Africa as well as selected institutions abroad. A formal delegate performance assessment system is used. The programme also has procedures in place through which extensive feedback from delegates is gathered and reviewed and used to drive incremental improvement of the content as well as the presentation style. The role of the active alumni network in sponsoring candidates for the programme as well as interacting with delegates is reviewed.

Fluorescence based fibre optic pH sensor for the pH 10–13 range suitable for corrosion monitoring in concrete structures

The design, development and evaluation of an optical fibre pH sensor for monitoring pH in the alkaline region are discussed in detail in this paper. The design of this specific pH sensor is based on the pH induced change in fluorescence intensity of a coumarin imidazole dye which is covalently attached to a polymer network and then fixed to the distal end of an optical fibre. The sensor provides a response over a pH range of 10.0–13.2 with an acceptable response rate of around 50min, having shown a very good stability over a period of longer than 20 months thus far. The sensor has also demonstrated little cross-sensitivity to ionic strength (IS) and also excellent photostability through a series of laboratory tests. These features make this type of sensor potentially well suited for in situ long term monitoring of pH in concrete structures, to enhance structural monitoring in the civil engineering sector.

사회간접자본 프로젝트의 CM제도 활성화방안에 대한 인식분석 연구

국내 사회간접자본(SOC) 프로젝트에서는 품질, 비용, 안전, 공정의 체계적이고 효과적인 관리를 위해 CM제도를 다양한 시범사업 및 실제 사업에 도입하고 있다. 그러나 국내 SOC사업에 CM제도를 도입하는 데는 여러 가지 실무적 장벽들이 존재한다. 내적으로는 안전문제 및 부실시공으로 인해 발생된 건설 산업에 대한 부정적인 시각을 극복하고, 외적으로는 건전한 시장개방과 국제화 및 세계화 시대에 부합하여 기술발전 및 개발을 통해 대외 경쟁력을 향상시켜야하는 과제를 안고 있다. 이를 달성하기위해 각 프로젝트 참여자들이 효율적으로 융화 될 수 있는 있는 토대를 제공하는 CM제도의 정착은 중요한 현안이다. 그러나 현재 발주처의 입장에서 국내 SOC 프로젝트 CM 제도의 정착화 방안을 객관적으로 규명하는 연구가 결여되어있다. 따라서 본 연구는 이를 규명하기 위해 국내 CM 프로젝트에 참여하는 구성원들(예, 발주처, 감리, 설계사, 시공사 등)을 대상으로 전문가 설문조사를 실시하여 CM도입에 대한 인식을 분석하고, 각 프로젝트 참여자들의 CM에 대한 입장을 정립하며, CM 정착을 위해 수반되는 문제점을 규명하고 이에 대한 대응 방안을 제시한다. 국내 SOC 프로젝트 CM에 대한 각 프로젝트 참여자들의 입장을 객관적으로 분석함으로써 CM 제도를 보다 효율적으로 정립하는데 기여한다. Current environment in civil and construction industry has changed to actively adopt construction management (CM) in various areas. While it is found that exemplary CM projects have been carried out in many civil engineering sectors, concrete system framework has not been suggested due to ambiguous boundary between CM and supervision system, unclear perception of CM's role, and inexperienced organization and regime. This paper investigated the challenges faced in civil and construction industry, and analyzed the strategy that could improve the current immature CM system by conducting questionnaire survey from experts in various construction sectors. The results could provide valuable information that can involve diverse opinions and view points in project participants.

Optimising building information modelling and off-site construction for civil engineering

Loughborough University and Halcrow are currently investigating how the whole civil engineering sector can benefit from incorporating innovations such as building information modelling and off-site construction. Vasileios Vernikos of Loughborough University explains.

Profiling emerging contractors for effective transformation in the South African construction sector

South Africa's construction industry is transforming. Its economy requires a wider base of contracting entities. Much of this growth is expected to be delivered by ‘emerging’ contractors. Yet these companies face significant obstacles. Targeted interventions that foster companies need a better picture of these firms and their core members. A survey of the civil engineering sector, targeting emerging contractors, showed that the owners of these companies lack training and experience, and that there are gender-related differences. Classifications according to company turnover, contract sizes or employee numbers alone do not reflect circumstances. Combining these data with the core members' backgrounds gives a clearer picture. Most companies hover between the ‘Existence’ and ‘Survival’ stages of business development. Development initiatives that assume companies require knowledge must accommodate large cognitive distances between sender and receiver. Initiatives thus need to focus on the owners, considering the status and background of their companies.

Exploring the International Difference on Building Steel Intensity

Steel is known as the most consumed metal in the world. Especially the use of steel in building and civil engineering sector accounts for the largest share in the total steel consumption. The flow and stock of steel has been intensively studied by material flow analysis (MFA) methodologies. The steel intensity for buildings largely depends on building structure, which is further decided by various factors, e.g. local economics, environment, frequency of earthquakes, culture, etc. However, these factors were seldom considered in previous MFA studies when estimating building steel stocks. In this paper, the worldwide difference in building structural composition was compared, and average building steel intensity was calculated. The authors examined the influence of GDP per capita, frequency of earthquakes, and average people killed per earthquake on the building structural composition, and the average building steel intensity. As the result, Asia-Pacific countries show relatively higher average building steel intensity than European countries, which is attributable to the seismic frequency. However, countries like China could have low average building steel intensity even with high seismic risk due to their low GDP per capita. These countries indicate high potential in growth of steel consumption in building sector in the future.

Challenges for Sustainability Assessment by Indicators

This paper presents an overview of sustainable construction in civil engineering from the perspective of project management and sustainability assessment through indicators. It discusses the different approaches and requirements of sustainability assessment models that are based mostly on criteria and indicators, the needs that are deemed critical for the application of sustainability indicators in the civil engineering sector, and the challenges that remain to be overcome before they can be applied in general practice. The ultimate goal is indicators that allow comparison not only between alternatives but also between projects in regard to sustainability certification.

LA RENTABILIDAD ECONÓMICA EXPLICADA A TRAVÉS DEL TAMAÑO. LAS EMPRESAS DE INGENIERIA CIVIL EN ESPAÑA

The profit and loss account shows the difference between incomes and expenses of a company during a financial year. However, the net income, as an absolute figure does not allow identifying the organizational efficiency or the efficiency in the use of resources. This explains the usefulness of economic profitability, among other indicators, to analyse efficiency. In this research, based on the analyses of the Spanish civil engineering sector, we have determined three ways to calculate the economic profitability, considering the operating income and three indicators of firm size. These indicators, proposed by the Spanish Accounting Plan as criteria to measure the size of the company, are the total amount of assets, the average number of employees in the financial year and the revenues from operations. The main objective of this work is two-fold. On one hand, we seek to group Spanish civil engineering firms in terms of their economic profitability. On the other hand, we try to determine the firm size indicators that characterize each group. Our findings show three groups of civil engineering firms in Spain, called star group, advance group and standard group. For each one of these categories, it has been determined which is the relationship between the different measures of economic profitability and the group assigned. The results show that the companies of the star group have a positive relationship with revenue from operations; companies of the advance group have a high return with regard to assets and a low number of employees; whereas the standard companies are been positively influenced by the number of employees and negatively by revenue from operations and assets.

Emerging contractors in South Africa: interactions and learning

PurposeThe South African construction industry is undergoing transformation. Part of this metamorphosis is the explosion in the number of “emerging contractors”. However, emerging contractors have a tendency to fail to develop into sustainable enterprises due to inadequate construction knowledge and lack of experience. These shortfalls can be potentially overcome by learning through appropriate interactions with others who possess the required knowledge and experience but there is an absence of comprehensive data about the form and frequency of such interactions and reliance has tended to be on small scale samples or anecdotal reports. The paper aims to address these issues.Design/methodology/approachA survey amongst emerging contractors on interactions in the civil engineering sector was carried out, collecting mainly quantitative but also qualitative data for analysis.FindingsSignificant relations between particular forms of interactions and knowledge perceived to be held by the respondents exist. Interdependencies between interactions and knowledge levels are present. Yet, the findings indicate that these interactions are not fully capitalised on in terms of knowledge gains by the respondents.Originality/valueUsing the conceptual framework of the Basho, as introduced by Nonaka, the knowledge of patterns of interactions with indicators of knowledge‐interaction interdependencies are of interest. Mapping these allows for the relevant existing learning contexts and knowledge transfer mechanisms to be explored and described.

Composite concrete/GFRP slabs for footbridge deck systems

In recent years the use of advanced composite materials has gained wider space in the civil engineering sector, due to some favorable characteristics such as lightweight, high specific strength, resistance to corrosion and fatigue. Innovative systems that combine concrete with advanced composite materials have proved to be a viable and efficient solution as compared to conventional systems. In this work, a new slab system composed of a fiber-reinforced concrete top laid on glass fiber reinforced polymeric (GFRP) wide-flange-section pultruded profiles, filled in with foam blocks, is presented. The material properties of the GFRP profiles were obtained both theoretically and experimentally. Experimental tests to choose the appropriate resin to bond the concrete to the GFRP profiles and to select the appropriate short fiber and volume fraction to be used in the concrete top have also been conducted. The slab was designed to sustain constructive loads and live pedestrian loads for footbridge deck applications. To investigate the slab flexural behavior up to failure, three specimens were tested under four-point bending, and theoretical and finite element analyses were also performed. Comparisons of theoretical, numerical and experimental results show good agreement. Studies under way to complete the development of the proposed slab are briefly described at the end of the work.

Structural Performance of Pultruded Composites under Elevated Temperatures

One of the major limitations for wider use of pultruded fiber reinforced polymeric (PFRP) composites in the civil engineering sector has been their behavior under elevated temperature and ultimately fire. This limitation arises not only due to the reduction in mechanical properties at high temperatures, including increased propensity to creep, but also due to limitations on the continuous working temperature causing permanent damage to the material as a result of thermal and oxidative degradation. Significant gains in property retention at high temperatures with crystalline polymers have been derived from the incorporation of fibrous reinforcement, but the development of new polymer matrices is the key for further elevation of the useful temperature range. This paper presents summary results of a research project focused on characterizing the viscoelastic behavior of commercially-produced, off-the-shelf unidirectional PFRP materials subjected to elevated temperature environments.

TerraSAR-X reveals the impact of the mobile barrier works on Venice coastland stability

Land subsidence and eustacy concurred to make the relative sea level in Venice (Italy) 23 cm higher over the last century. In order to protect the city and its lagoon environment from increased flooding, a series of mobile barriers are under construction at the three inlets of Lido, Malamocco, and Chioggia connecting the Adriatic Sea to the inner water body. Since 2003 work has been proceeding with the reinforcement and extension of the existing jetties and the construction of breakwaters, harbors, and a small island within the Lido inlet. We detected significant local settlements of a few centimeters between March 2008 and January 2009 at the three inlets induced by the construction works through an interferometric analysis of 30 satellite radar images acquired by the new German TerraSAR-X mission. On a more regional scale we observe that the city of Venice and the other major urban settlements on the lagoon littorals are not impacted by subsidence during this period. The very high spatial resolution of 3 m and the short repeat-time interval of 11 days of TerraSAR-X enable the investigation of displacements with an unprecedented observed level of details, opening new perspectives to geodynamic's research and civil engineering sectors for the monitoring of large infrastructures with potential vulnerability to terrain motion.

Business definition and performance implications: the case of the Belgian construction sector

Business definition (either explicitly or implicitly defined) matters in the construction sector in Belgium. A business is a three‐dimensional ‘strategic space’ within an industry, defined by the buyer types targeted, product types sold and geographical reach. The research setting is one of family owned small non‐diversified firms in the construction industry. The sample consists of 61 firms. Data on these firms were gathered for the year 2006. Firms with a similar business definition within the construction sector were clustered. Three clusters could be delineated: residential, non‐residential and a civil engineering business. Performance differs between the three businesses. Performance was measured with perceptions on sales, sales growth, gross sales margin and return on invested capital. Perceived performance correlated with financial performance. Competitive forces differ according to the business. Firms in the civil engineering sector working for government agencies performed best.

Process Modelling in Civil Engineering

This article describes the use of process-modelling techniques in civil engineering. Process modelling is regarded as a key competence in different economic sectors. Civil and structural engineers execute complex processes. This article explains why existing modelling techniques are not suitable for the specific class of processes in civil and structural engineering. Modern approaches are presented that were investigated at Technische Universität Berlin to model civil engineering processes more efficiently so that complete, consistent and correct process descriptions can be derived. These approaches have been tested in real projects. Extracts of examples are given to illustrate the use of the modelling techniques. The application of these approaches requires new modes of working, but these approaches are suitable for processes in civil and structural engineering. The article concludes with an outlook where open questions are discussed about how the civil engineering sector and therefore also structural engineers can benefit from suitable process modelling techniques.

Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050

This study addresses the question of how much carbon will be sequestered in wood products during the coming decades in Finland. Using sawnwood and other wood material consumption data since the 1950s and inventory data of carbon reservoirs of wood products in the Finnish construction and civil engineering sector, we first derive estimates for the carbon reservoirs in wood products-in-use in that sector. We then extend the estimate to include all wood products-in-use. We find that the carbon pool of wood products in the Finnish construction and civil engineering sector grew by about 12% since an inventory for 2000, and that the overall estimate for carbon reservoirs of Finnish wood products in 2004 was 26.6 million tons of carbon. In building the scenarios until 2050, econometric time series models accounting for the relationship between wood material consumption and the development of GDP were used. The results indicate that the range of carbon reservoirs of wood products in Finland will be 39.6–64.2 million tons of carbon in the year 2050. The impacts of different forms of the decay function on the time-path of a carbon sink and its value in wood products were also studied. When a logistic decay pattern is used, the discounted value of the predicted carbon sink of wood products in Finland is between EUR850 and EUR1380 million – at the price level of EUR15/CO ton – as opposed to 440–900 million euros, if a geometric decay pattern is used.2

Lightweights at the construction site

There are numerous applications for composites in the civil engineering sector. Marcus Reichl reports.

Getting the mix right? The use of labour contract alternatives in UK construction

PurposeThe purpose of this paper is to examine the use of contingent labour in the construction and civil engineering sector in the UK.Design/methodology/approachThe paper presents the findings of a national postal survey of employment practices within the UK construction and civil engineering sector. The survey was conducted in 2002 and covered firms of all sizes within the sector. This technique has been supplemented with in‐depth interviews to provide a deeper understanding of the issues raised.FindingsThe paper finds that employers' use of contingent labour is widespread and that in many cases, the use of contingent labour has increased over recent years. It is argued that recourse to the use of contingent labour may increasingly be a constrained choice for employers, reflecting overall labour shortages and recruitment difficulties in the sector. The paper also finds that the use of contingent labour contributes to skills shortages in the industry, with the scope of training offered to workers on these contract forms being limited in nature.Originality/valueThe paper reveals the complex relationship between the use of contingent labour and ongoing skills shortages in the sector. The paper concludes that the cycle of turning to contingent labour in response to recruitment difficulties does not replenish the skill profile of the sector and therefore offers no long‐term solution to the skills shortages within the construction industry.

A Flow Time Model for Melt‐Cast Insensitive Explosive Process

AbstractDiphasic flows of concentrated suspensions of melt‐cast insensitive explosives exhibit specific rheological properties. In order to limit the handling of pyrotechnical products presenting a risk with respect to the mechanical and thermal shocks, a lot of work has been undertaken for many years in the civil engineering sector. The objective of this study is to propose a predictive model of the flow time of a concentrated suspension through a nozzle located at the bottom of a tank. Similar to our industrial process, the suspension is made out of insensitive energetic materials and flows under gravity. Experimental results are compared to three models (Quemada, Krieger‐Dougherty, and Mooney) predicting the viscosity μ of a suspension as a function of the solid volume fraction ϕ, the maximum packing density ϕm and the viscosity μ0 of the interstitial liquid. De Larrard's model is used to calculate ϕm. The value of viscosity measured for the pure liquid is close to the one predicted by the Bernoulli theorem, where liquids are considered as incompressible and inviscid. Finally, it was found that the Quemada's model gives a fair agreement between predictions and experiments.

Applications of Fiber Bragg Grating Sensors in the Composite Industry

AbstractOptical-fiber sensors based on fiber Bragg gratings (FBGs) provide accurate, nonintrusive, and reliable remote measurements of temperature, strain, and pressure, and they are immune to electromagnetic interference. FBGs are extensively used in telecommunications, and their manufacture is now cost-effective. As sensors, FBGs find many industrial applications in composite structures used in the civil engineering, aeronautics, train transportation, space, and naval sectors. Tiny FBG sensors embedded in a composite material can provide in situ information about polymer curing (strain, temperature, refractive index) in an elegant and nonintrusive way. Great improvements in composite manufacturing processes such as resin transfer molding (RTM) and resin film infusion (RFI) have been obtained through the use of these sensors. They can also be used in monitoring the “health” of a composite structure and in impact detection to evaluate, for example, the airworthiness of aircraft. Finally, FBGs may be used in instrumentation as composite extensometers or strain rosettes, primarily in civil engineering applications.