To study the pull-out behavior of torque-controlled expansion(TCE) anchors on high-performance concrete(HPC) and high-performance fiber-reinforced concrete(HPSFRC) substrates, 28 pull-out tests are ...set up. Different installation conditions of anchors, including the embedment depth(Hef) and the preload torque(Tinst), and the types of substrates, including no-fiber HPC and HPSFRC with 1% fiber content, are considered in the test. The split tensile(ft) and compressive strengths(fcu) of concrete are measured to evaluate the influences of fibers on the properties of concrete. Pull-out tests are conducted TCE anchors installed in C70 HPC/HPSFRC cylinder specimens by the displacement-control loading method. From test results, the relationship between failure mode, load-displacement behavior, pullout load-bearing capacity(Nu) and installation factors (Hef, Tinst, etc.) are analyzed. The preload loss law of the fastener system within 24 h is monitored. It is found that the larger Tinst leads to a larger preload loss rate, and the loss in Tinst tends to be stable within 5–7 h. A modified model of Nu of TCE anchors in HPSFRC is proposed. The prediction accuracy of the modified model and the existing models (CCD model, Toth et al's model) is compared; both CCD and Toth et al's model underestimate Nu, which would lead to uneconomical over-design, and the prediction results of the modified model are in a good agreement with the experimental results.
The purchase contract for government-supplied materials, which means materials provided by the owner in public construction works, has various delivery conditions. Controversy has continued between ...public agencies such as the Public Procurement Service and construction contractors over the appropriateness of application of the purchase contract with on-site installation conditions, and the Anti-Corruption and Civil Rights Commission (ACRC) made recommendations in 2012. Nevertheless, public agencies continue to actively apply product purchase contracts with on-site installation conditions. In this study, total on-site installation related costs was defined as the sum of direct labor costs, equipment expenses, and other related interlocking costs. As a result of analyzing the total on-site installation related costs of government-supplied materials from the actual construction cost data of 25 construction works, it accounted for an average of 4.49% of the estimated price. If the ratio of 4.49% to the 37.5 trillion won estimated as the average amount of public construction projects in Korea is reflected, the annual on-site installation related costs is about 1.6838 trillion won. It can be confirmed that the proportion of on-site installation related costs of government-supplied materials in the construction market is substantially significant.
This study presents an automatic tool developed for the optimisation of the layout of offshore inter-array cable systems. Employing stochastic approaches, this tool can quickly find a near-optimum ...cable connectivity solution based on one of the criteria including capital expenditure (CAPEX), operational expenditure (OPEX), or their combination considering the net present value over the project lifespan. The seabed geo-tech constraints are considered to minimise cable routes across seabed areas where challenging installation conditions may exist, and to avoid cable routes across the seabed areas where the installation is impossible. The tool employs advanced identification of suitable locations of multiple offshore substations for large wind farms. This optimisation tool is coded in Python 2.7 and scripted IPSA + is used as the load flow calculation engine for power loss calculation. This tool has been applied to 4 GW offshore wind projects developed in European and Asian waters and it is demonstrated that the tool automates the design for the inter-array cable system layout and delivers measurable overall project efficiency gains. Comparisons were made between radial design and branched design; it is shown that the branched design can achieve better cost savings than the radial design.
The installation condition of heat meters has an influence on interior fluid field and flux measurement accuracy. In this paper, this influence is investigated through experimental research and ...numerical simulation. The results indicate that the influence of the length of tubes in front of heat meters can be neglected when L≥4D (L is the length of tubes in front of heat meter, D is the diameter of heat meter). This conclusion has been of great value on academic theory and practical application.
Based on previous research results, this study aims to analyze the effects of changes in the amount and area sprayed with bonding agents to improve the seaming strength of woven geotextiles used as ...soft ground reinforcement materials. After evaluating the engineering properties and considering the installation conditions of the reinforcement materials, the reduction factor affecting the reinforcement of the seamed area was calculated and the long-term allowable seaming strength was investigated. To confirm the effects of bonding agents on reinforcing woven geotextile seamed areas, we considered each of the following field installation condition factors: installation resistance, chemical resistance, salt water resistance, and shear frictional resistance. The results of this study show that there is a method that can improve the soft ground and its stability by improving the retention of the seaming strength of woven geotextiles by effective bonding agent application.
The paper describes the results of both experimental tests and numerical parametric studies aimed at a better understanding of the structural behaviour of closely packed circular-shaped sewer ...linings. First, the structural responses of complete and segmental linings are compared analytically. Then, vacuum tests carried out on circular glass-reinforced plastic linings to simulate the effect of grouting the annulus gap during installation are reported. Finally, the effect of various restraint conditions, which simulate different temporary support systems that may be used by the contractors during installation of the lining, are investigated; in view of the predominantly membrane response of circular linings to continuous (i.e. flotation and uniform-pressure) loading, approximate design curves, based on a simplified buckling criterion, are presented.
Solar chimney as a reliable renewable energy system has attracted increasing attention from engineers to conquer the current energy crisis. The main challenge of designing a solar chimney is to ...optimize its performance with the lowest cost. Based on literature review, thirteen key influencing factors were obtained and classified into four groups, including configuration, installation conditions, material usage, and environment. Statistics of experimental studies showed that the overall tested range is still limited which suggests more future experiments. To enhance the performance, a solar chimney is suggested with possible high cavity and solar radiation, a cavity gap of 0.2–0.3 m, equal inlet and outlet, a height/gap ratio of around 10, an inclination angle of 45–60° (for roof solar chimney considering latitude), an appropriate opening of room, double/triple glazing, a 5 cm thick insulation wall, and a solar absorber with larger absorptivity and emissivity. These optimum values may not be applicable to all configurations as they are interdependent. Although external wind shows significant influence on solar chimney, solar chimney design can be undertaken without considering the effects from wind. This review will provide a useful technical guide for researchers and professionals regarding the optimum designs of solar chimney in buildings.
