Civil Engineering Laboratories Research Articles

Optimizing compressive strength prediction using adversarial learning and hybrid regularization

The infrastructure industry consumes natural resources and produces construction waste, which has a detrimental impact on the environment. To mitigate these adverse effects and reduce raw material consumption, waste materials can be repurposed to achieve sustainability. However, recycled materials deteriorate the intrinsic properties of concrete. A suitable ratio of natural resources and recycled aggregates can produce the desired compressive strength. Compiling sufficient data in civil engineering laboratories to make reliable conclusions is time-consuming and costly. Therefore, this research proposes a novel approach for predicting compressive strengths using limited data. The generative adversarial network was employed to generate synthetic data. Hybrid training, utilizing either conventional loss or heuristic loss, prevents the model from overfitting by adaptively adjusting the regularization term. Random noise from a multivariate normal distribution is embedded heuristically into the training samples to capture intricate data variations. Sensitivity analysis indicated that the size of recycled coarse aggregate and water are the most significant features, aligning with their correlations. Interestingly, superplasticizer, density of recycled coarse aggregate, and water absorption ratio of recycled coarse aggregate contributed significantly to predictions despite their low correlations. The propounded method outperforms random forest, support vector regression, artificial neural network, and adaptive boosting by scoring a mean squared error of 7.97, a root mean squared error of 2.82, a mean absolute error of 2.13, and a coefficient of determination of 0.96. These results suggest that the proposed technique can effectively contribute to sustainable construction practices by accurately predicting compressive strengths.

Mitigation strategies to reduce particulate matter concentrations in civil engineering laboratories

In the departments of civil engineering, many experiments are conducted in laboratories for educational and research purposes. Varying degrees of respirable dust are generated as the outcome of these experiments, which could cause harm to instructors’ and students’ health. This study is devised to highlight the importance of indoor air quality in university laboratories. As part of the research, four different particulate matter (PM) sizes (PM1.0, PM2.5, PM4.0, and PM10) were measured during specific experiments—sieve analysis, preparation of the concrete mixture, crushing aggregate by jaw crusher, dynamic triaxial compression test, sieve analysis of silt specimen, cleaning sieve by an air compressor, and proctor compaction test—being conducted periodically in the laboratories of civil engineering departments. The measured values are mainly high compared to indoor air quality standards. Mitigation strategies were applied to reduce indoor air PM levels in the three experiments that contained the highest PM levels. The results have shown that mitigation strategies applied as control measures could make a remarkable difference in protecting instructors and civil engineering students.

Design, Validation and CFD Modeling of an Environmental Wind Tunnel

The wind erosion of granular materials stored within the open yards of industrial plants (i.e., industrial wind erosion) and the subsequent emission and dispersion of particulate matter (PM) in the surrounding areas represent an important issue for the exposed population and for the environment as a whole. The Environment Impact Assessment (EIA) and the design of emission control measures require a deep knowledge of the erosion phenomenon, and the precise estimation of the Emission Factors (EF) associated with the specific PM source under investigation. Aiming to characterize the emission potential of industrial granular materials, a new Environmental Wind Tunnel (EWT) has recently been built at the Department of Civil and Environmental Engineering and Architecture (DICAAR) laboratories, in Cagliari University. The article discusses the EWT’s updated design and the set-up methodologies applied to reproduce the Atmospheric Boundary Layer (ABL) acting over the surfaces of coarse and heterogeneous granular materials. In addition, a Computational Fluid Dynamics (CFD) model of the EWT has been developed to reproduce and analyze the wind field throughout the entire tunnel volume and preliminarily evaluate possible modifications to the original design. The accuracy of the simulation has been verified by comparing the CFD model and the results of the experimental tests.

Evaluation of mortar properties by combining concrete and brick wastes as fine aggregate

Construction and demolition waste (CDW) valorization in a new production process has been widely studied. However, up to now, valorization has been limited to use one type of waste. Hence, the environmental and economic benefits remain quite narrow, particularly in countries with high waste production. This paper aims to determine the feasibility of using waste from rejected concrete specimens by civil engineering laboratories combined with waste brick, as an alternative of natural fine aggregate in the production of cement mortar. Natural fine aggregate (NFA) has been replaced by recycled fine aggregate (RFA), at 0%, 15 %, 30 %, 45 %, and 90 %, by weight. In this study, RFA from concrete and brick wastes were firstly characterized and compared to the NFA. Then several tests were carried out in order to evaluate the effect of RFA on mortars. The RFA’ physical, mineralogical and microstructural properties prove to be different from those of NFA. Nevertheless, the results have shown that the incorporation of these RFA at 15 % do not have any negative effect on the mechanical performance of the mortars. Besides, the microscopic analysis has revealed that the addition of RFA doesn’t compromise the microstructural properties of the mortars at low substitution rates. As a whole, this study shows that the use of RFA is possible.

Assessing the Safety Risks of Civil Engineering Laboratories Based on Lab Criticity Index: A Case Study in Jiangsu Province.

With the rapid development of the construction industry, an increasing amount of attention were paid by universities to the development of civil engineering experiment courses so as to improve the practical research abilities of students. In recent years, due to the frequent occurrence of civil engineering laboratory accidents, it has become an urgent issue regarding on what factors influencing safety risks and how to assess and reduce the safety risks in civil engineering laboratories. Based on the lab criticity index (LCI) model, the research specificities of civil engineering laboratories were analyzed through literature review and expert interviews and 13 risk factors of civil engineering laboratories, from the four aspects of man, object, management, and environment, identified. The data for each parameter in the LCI model was obtained through a questionnaire survey, and finally the LCI value was calculated to evaluate priority. Among them, insufficient safety awareness of operators, danger due to equipment failure, imperfect management policies, and complex floor conditions were listed as the most common risk factors. Based on the LCI model, the worsening factors of these four risk factors were further analyzed. The LCI model is applied to the new research field of safety risk assessment in civil engineering laboratories that few researchers have studied before and a risk list for civil engineering laboratories was created. We revealed the safety status of civil engineering laboratories in Jiangsu Province and provided feasible suggestions for improving the management and supervision of civil engineering laboratories at universities. It can strengthen operator awareness of the risks in civil engineering laboratories and improve the social group’s attention to the safety risks of the laboratories, thus reducing the accidents’ possibility and seriousness of civil engineering laboratories.

Evaluating noise exposure levels of laboratories in civil engineering education

One of the most highly found physical contaminants in the working environment is noise, which cause negative health effects associated with the hearing system that could lead to temporary or permanent deafness. Therefore, occupational noise is a risk that is being monitored at work places by measuring exposure levels and developing preventive measures. However, there are certain work places, such as laboratories used for research and education, which are not usually considered to be noisy, even though some activities could generate harmful noise levels for laboratory personnel and students. This study aimed to evaluate and highlight the risks associated with civil engineering laboratories, where noisy experiments are conducted on a regular basis. Thirteen commonly conducted experiments from four different civil engineering areas were selected for measurement. The highest noise exposure levels of each experiment were determined and compared with the limits imposed by different regulations and standards. The results showed that three of the experiments (grinding aggregate by ball grinder, crushing aggregate by jaw crusher and cutting concrete by saw) generate noise above the limits determined by standards and regulations. Preventive measures to reduce noise levels for these experiments were recommended and a noise control flow chart for similar work environments was presented.

Alternative Setup Apparatus to Test ASTM A944-10 Beam-End Specimens

Abstract The setup apparatus described in ASTM A944-10, Standard Test Method for Comparing Bond Strength of Steel Reinforcing Bars to Concrete Using Beam-End Specimens, is designed to apply the load horizontally with respect to the laboratory floor. However, many civil engineering laboratories currently use (or have access to) rigid testing frames designed to apply the load vertically. Thus, a setup apparatus adapted to the current frames in use and alternate to the one described in ASTM A944-10 was developed and is thus presented. Following a brief review of the major characteristics of a typical ASTM A944-10 beam-end specimen, the proposed setup apparatus and the procedure to mount and test the specimen are described. Thereafter, the results of three groups of specimens having three replicas each are presented and are followed by a discussion on how to interpret and analyze the information obtained from the test.

Problems Related to the Siting of the Laboratory Building for Civil Engineering Department at the University of Warmia and Mazury in Olsztyn, Poland

This paper deals with the conditions underlying and the problems arising from the siting of a building with specialist laboratories in a developed part of the university campus in Olsztyn, Poland. The topography of the terrain and the need to house civil engineering laboratories in the planned building had an immense impact on the shape of the building and consequently on its foundations, whose dimensions responded to the ground conditions and the specification of various loads they would have to support, including the equipment for the laboratories. The siting of a building as a step in the construction process entails several problems, which are first taken into consideration at the stage of making preliminary concept plans and are subsequently verified while working on the final construction plan. The required information included geotechnical documentation, survey of the ground conditions and the data regarding the predicted loads on the building, necessary to select the right type of foundations. All these problems grow in importance when dealing with such unique buildings like the discussed example of a laboratory building for the Civil Engineering Department, built on a site within a conservation zone on the campus of the University of Warmia and Mazury in Olsztyn, Poland. The specific character of the building and the specialist equipment with which it was to be furnished (a resistance testing machine, a 17-meter-long wave flume) necessitated a series of analyses prior to the siting of the building and selecting suitable foundations. In turn, the fact that the new building was to be erected in the conservation zone meant that collaboration with the Heritage Conservation Office had to be undertaken at the stage of making the plan and continued during the construction works. The Heritage Officer's recommendations concerning the building's shape, divisions, dimensions, materials used, etc., created a situation where the team of designers and architects had to become engaged in the process of landscape and spatial management. The above requirements concerned the functions of the building and its siting on a land parcel that was difficult to handle, also because of the protected trees growing there. Other constraints included the small size of this site, the developed surroundings, and the pre-defined programme of functions and use of the new building. On the other hand, the siting of the planned building had to be accommodated to the existing underground infrastructure (utilities). All the above circumstances made the task difficult and demanded good coordination between individual teams of engineers and architects, both at the stage of making the plan and during the construction works.

Reliability Pointers for Modal Parameter Identification of Grandstand Terraces

The reinforced concrete terrace units were positioned and tested on a specially manufactured steel frame resting on the strong floor in the Civil Eng ineering laboratories at Coventry University. In parallel, a finite element model was developed and set to free v ibration. Natural frequencies and mode shapes were recorded and compared with those obtained experimentally. As correlation was not deemed to be satisfactory, an updating process was init iated and a series of parameters, starting with the concrete material properties were rev ised to imp rove links with the experimental results. Boundary conditions built-in the code were not adequate to model the real behaviour of the structure. Best results were achieved when supports conditions were modelled with a stiffness matrix. Correlation between experimental and co mputer predicted results improved further with the introduction of more advanced modelling techniques and gradual lifting of the limitations of the model, hence assisting the validation process, while verificat ion did not provide the expected degree of confidence. It was concluded that it is possible to extract the natural frequencies and mode shapes of a complex, non-symmetric structure accurately, by using relat ively low-cost, basic modal testing equip ment and the finite element method of analysis, hence avoiding the risk of not detecting any mode shapes. This can be more apparent in complex modes (e.g. coupled, flexu ral/torsional) as they depend greatly on the number, position, d irection, type and quality of the transducers and data logging and processing equipment used. Emphasis is placed on the experience built up in interpreting modal analysis results in order to be used for similar future work.

Prediction of compressive and tensile strength of limestone via genetic programming

Accurate determination of compressive and tensile strength of limestone is an important subject for the design of geotechnical structures. Although there are several classical approaches in the literature for strength prediction their predictive accuracy is generally not satisfactory. The trend in the literature is to apply artificial intelligence based soft computing techniques for complex prediction problems. Artificial neural networks which are a member of soft computing techniques were applied to strength prediction of several types of rocks in the literature with considerable success. Although artificial neural networks are successful in prediction, their inability to explicitly produce prediction equations can create difficulty in practical circumstances. Another member of soft computing family which is known as genetic programming can be a very useful candidate to overcome this problem. Genetic programming based approaches are not yet applied to the strength prediction of limestone. This paper makes an attempt to apply a promising set of genetic programming techniques which are known as multi expression programming (MEP), gene expression programming (GEP) and linear genetic programming (LGP) to the uniaxial compressive strength (UCS) and tensile strength prediction of chalky and clayey soft limestone. The data for strength prediction were generated experimentally in the University of Gaziantep civil engineering laboratories by using limestone samples collected from Gaziantep region of Turkey.

Shake, Rattle, and Roles: Lessons from Experimental Earthquake Engineering for Incorporating Remote Users in Large-Scale E-Science Experiments

While there has been substantial interest in using e-science and cyberinfrastructure technologies to enable synchronous remote participation in experimental research, the details of such participation are in question. On the one hand, there is a desire to give remote participants the same views and capabilities that they would have as local participants. On the other hand, there are settings where experimental specimens and apparatus are large and difficult to manipulate effectively or view from a remote vantage point. This article argues for more novel forms of remote participation by drawing on exploratory interview and observation data gathered in civil engineering laboratories. It is shown that, while experiments are in progress, the engineers studied focus primarily on detecting and preventing specimen failures, and that their unease about remote participation stems from doubts about the ability of remote participants to detect failures adequately. It is argued that this presents the opportunity to consider novel roles for remote participants that exploit the features of e-science technologies.

Selection of the most appropriate method to determine the carbonate content for engineering purposes with particular regard to marls

Because of the influence of carbonates on the geotechnical properties of foundation and construction materials in civil engineering, a simple, precise, and inexpensive method of determining soil-carbonate content is needed. A large number of methods exist to determine the carbonate content in soils; but, for diverse reasons (precision (accuracy), cost, sensitivity, etc.) not all are appropriate in a civil-engineering laboratory. In the present work, different laboratory methods to determine the carbonate content in soils have been compared in order to choose the most appropriate one. The most suitable method has been selected on the basis of a number of general criteria: precision (accuracy), equipment cost, operating and maintenance costs, staff requirements, and sensitivity of the equipment. According to these general criteria, three methods can be considered suitable: flame photometry, volumetric calcimeter, and EDTA complexometry. These three methods present errors of less than 5%, involve low to medium cost, and the maintenance operations are simple. In addition, a suitability index has been defined (depending on three specific criteria: degree of precision (accuracy), level of standardization, and suitability of the operation method and type of ion analysed) which enabled the selection of the most appropriate from among the three methods. For the study, marl samples were taken from quarries used to construct the impermeable cores of three dams in the upper Guadalquivir River Basin (S Spain), as well as Standard samples were made with pure and inert calcium carbonate. Finally, it is concluded that the volumetric method (Bernard calcimeter) is the overall best technique to determine the carbonate content in civil-engineering laboratories.

Use of microcomputers and data logging systems in civil engineering laboratories : Prince, A; Calleran, M E Ground EngngV19, N6, Sept 1986, P34–35

Use of microcomputers and data logging systems in civil engineering laboratories : Prince, A; Calleran, M E Ground EngngV19, N6, Sept 1986, P34–35

Assuring Quality Civil Engineering Education

Two aspects of the support needed for a quality civil engineering education are examined: Services, including staff and operations; and facilities, particularly as related to equipment needs. At major research universities, facility needs for civil engineering are greater than those for electrical and mechanical engineering. Civil engineering's laboratories serve as this nation's applied technology laboratories, which is not the case for electrical and mechanical engineering. Only a dynamic “hands‐on” educational program produces graduates that are knowledgeable technically, responsive socially, and programmed for change in both areas. Such a program requires budgets per yer per faculty of at least $5,000 for operations and $10,000 for equipment. Typical university budgets are $3,000 for operations and $1,500 for equipment, and such budgets provide only an outdated “hands‐off” education.

The Underwater Laser Surveying System: A New Concept

In January of 1969 under contract to the Naval Civil Engineering Laboratories (NCEL), TRW delivered to Project TEKTITE an underwater surveying system which utilized a portable, pulsed ion, argon gas laser as the reference light source. The intent of the system was to demonstrate the feasibility of conducting standard surveying operations by constructing several different size rectangles on the floor of the ocean and measuring the contours in the area of these rectangles. In addition, the actual location of the laser and the orientation of the rectangular plot was to be accurately located relative to reference points on a shoreline considered inaccessible to the divers. The Underwater Laser Surveying System (ULSS) has successfully met or exceeded all design objectives.

New Laboratories at the University of Liverpool: Civil Engineering and Building Science Laboratories

New Laboratories at the University of Liverpool: Civil Engineering and Building Science Laboratories

End anchorage and bond stress in prestressed concrete

Summary: Research into the properties and problems of prestressed concrete has been pursued for some ten years in the Civil Engineering Laboratories of Leeds University and this paper deals with the results of tests on prestressed concrete columns to find the transmission lengths required to ensure complete bond between the wires and the concrete. It is seen that the initial transmission length for 0·2 inch diameter wires stressed to 70 tons per sq. in. is about 125 diameters (25 in.) and for 0·08 inch diameter wires stressed to 100 tons per sq. in. about 60 diameter (5 in.). These values apply only if the concrete is of good quality. It is seen that bad placing can cause these transmission lengtlrs to be greatly increased. A transmission length of approximately 400 diameters was measured in badly placed concrete. It is recommended that som~ form of mechanical locking device should be used when structures of short length are to be prestressed by 0·2 in. diameter wires. The use of 0·08 in. wires eliminates any uncertainity with regard to the end anchorage.

The strength of reinforced concrete beams in shear

Summary: The determination of the magnitude and distribution of the shearing stresses in reinforced concrete beams is one of the most difficult problems that faces designers at the present time. A research programme has been pursued for some two years in the Civil Engineering Laboratories of Leeds University and this paper deals with the results of tests on 39 beams designed to fail in shear or diagonal tension. Many factors influence the resistance of reinforced concrete in shear and the factors investigated so far are the effects of variations in (a) spacing of vertical stirrups and percentage web reinforcement, (b) ratio of depth of beam to the span. It is seen that vertical stirrups, even with spacings a little greater than the moment arm, always increase the ultimate shearing loads, the effectiveness of the stirrups falling gradually when the spacing exceeds about one-half the moment arm. The widths of inclined cracks in beams with mild steel vertical stirrups were less than 0·005 in. at a stress of 18,000 lb. per sq. in. and with square twisted steel stirrups about 0·006 in. at 25,000 lb. per sq. in. Vertical stirrups usually attain their ultimate strengths and, in shallow beams, a load factor of 2·5 is satisfactory. The capacity of doubly-reinforced beams to resist shear, in virtue of an action analagous to that of an open-frame girder, is considerable. A comparison is made of the observed shearing failing loads with the loads derived from British and American Codes of Practice from which it is seen that the present British Code of Practice is too conservative.

Canadian Snow Research

A recent event of great importance has been the inception of officially sponsored snow research in Canada. Hitherto large scale snow research has been almost entirely restricted to the Swiss and it is good to know that the Empire with its enormous opportunities will now be playing its part. The connection between the mechanics of soil and the mechanics of snow has been obvious for several years in Switzerland where the resources of the civil engineering laboratories have been made available for snow research. Dr. R. Haefeli, originally a civil engineer and head of the soil research department of the Eidgenossische Technische Hochschule in Zürich, has now become one of the foremost authorities on snow and ice. It is satisfactory to learn that this connection of ideas is being followed up in Canada. In England too a start has been made.

Canadian Snow Research

A recent event of great importance has been the inception of officially sponsored snow research in Canada.Hitherto large scale snow research has been almost entirely restricted to the Swiss and it is good to know that the Empire with its enormous opportunities will now be playing its part. The connection between the mechanics of soil and the mechanics of snow has been obvious for several years in Switzerland where the resources of the civil engineering laboratories have been made available for snow research. Dr. R. Haefeli, originally a civil engineer and head of the soil research department of the Eidgenossische Technische Hochschule in Zürich, has now become one of the foremost authorities on snow and ice. It is satisfactory to learn that this connection of ideas is being followed up in Canada. In England too a start has been made.