A Space State Forecast Model for Dam Construction Equipments Based on Analysis Prediction Theory

Anti-collision equipments system is developed to solve the collision problems of dam construction equipments, and in the system the determination of equipments＇ space state is important. A uniform moving equation of equipments is established based on the analysis prediction theory and the movements states of equipments. Method of least square was employed to deal with discrete data of equipments＇ space position. Fitting equation matched with the movement equation was presented to do data fitting, and a relevant algorithm was given. Applying the fitting equation, current and future space state of equipments can be accurately predicted. Finally, a case is given and results show that numerical values of data were steady and their precision was high. In LongTan dam construction of the equipments antiollision system, applying this method to forecast the equipments＇ space states and practical running of the system indicate that this method can improve the precision of position, obtain the better forecasting effect and increase the robustness of the system.

Research on Reform and Innovation of Curriculum System of Construction Equipment Specialty based on BIM application

BIM technology entered China at the beginning of this century and has played a prominent role in many industries,Firstly,it is applied in design enterprises,and then extends to construction enterprises,with emphasis on construction engineering.As the main force in the development of the construction industry,construction enterprises pay more and more attention to the learning and application of BIM in enterprises.BIM technology will bring more possibilities to construction equipment.With the development of The Times,the original teaching technology has been unable to meet and achieve students'future career needs and goals.This paper follows closely the steps of teaching reform,With the application of BIM technology as the entry point.The reform and innovation of BIM are deeply integrated into the professional core courses,curriculum design and graduation design,etc,in order to keep up with the industry demand and employment guidance,improve the social competitiveness of student’s employment.

New Method for Studying Rock-Breaking Mechanism by Disc Cutters

Gaining a thorough understanding of the theoretical principles of rock breaking with a disc cutter is a critical issue in tunnel boring machine (TBM) technology. To fully consider the complexity and importance of the basic principles of rock breaking during tunnel excavation, in this paper we use a new method, the smooth particle hydrodynamics (SPH), to study the rock-breaking mechanism and verify its accuracy and feasibility. Using the SPH method, we induce the rock fragmentation process with two cutters in synchronous and sequential orders. The results show that when the cutters act on rock sequentially, the second indentation influences the crack evolution of the first indentation. With increased cutter spacing, the second crack gradually becomes independent of the first crack. Under synchronous action of the two cutters, a bursiform nucleus is generated beneath the cutters and the area of the nucleus increases with increased cutter spacing. Whether the cutters act on the rock sequentially or synchronously, we found the optimum cutter spacing of our chosen rock type to be 60 mm. Our analyses results show that the efficiency of sequential rock cutting is superior to synchronous cutting, both with respect to crack evolution and cutter force. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Exhaust emission inventory of typical construction machinery and its contribution to atmospheric pollutants in Chengdu, China

To study the emission characteristics of typical construction machinery in Chengdu,12 construction machinery (excavators,bulldozers,loaders,and forklifts) under idling mode,moving mode,and working mode,were tested using a portable emission measurement system(PEMS).Under three operating modes,the typical construction machinery in the working mode was higher in the fuel-based average emission factors of PM_(2.5)and NOx,while the fuel-based average emission factors of HC and CO were higher in idling mode.Integrated the results of investigation on ownership and activity levels of construction machinery,an exhaust emission inventory of typical construction machinery of Chengdu in 2018 was established according to the recommendation method.The annual emission of PM_(2.5),NOx,HC,and CO were 1.67×106,1.61×108,3.83×106,and 1.26×107kg,respectively,and the excavator contributed the maximum emissions,accounting for an average proportion of 43.95%.The emission of construction machinery in Chengdu exhibited a clear monthly trend,with the highest from April to October and the lowest from November to March.In addition,the exhaust emissions presented an obvious spot-like characteristics,and the high-value areas were mainly concentrated in the surrounding suburban counties such as Shuangliu Wenjiang etc.To reduce pollution from construction machinery and improve the quality of the atmospheric environment,more effective measures on housing construction and municipal construction should be taken in those districts in Chengdu.

A Computer Model for Selecting Equipment in Earth-Fill Dam Projects

Selecting right equipment has been playing an important role in the success of construction projects. This paper presents a computer model, ESCMODEL, for equipment selection in Earth-fill dam projects. The proposed model is capable of assisting the users in making decisions to determine the size, number, type and schedule of presence of dozers, loaders, graders, excavators, trucks, sheepsfoot rollers and smooth wheel rollers. ESCMODEL can contribute to resolve this selection process through the application of an optimization technique, based on nonlinear programming. Three actual case studies of earth-fill dam projects are presented in order to illustrate the effectiveness and performance of the model.

Analyzing sustainability of construction equipment in the state of California

Construction equipment encompasses highly polluting machines adversely affecting the environment.Management tools are necessary for sustainability assessment of construction equipment fleets to allow contractors to reduce their emissions and comply with local or federal regulations. In addition to management tools, there is a need for a metrics that will allow companies to accurately assess the sustainability of their construction equipment fleets. The State of California USA is adopting innovative approaches to reduce adverse impact of humans on the environment. Once successfully implemented, the chances are that such practices attract other states to adopt similar approaches. This paper presents an evaluation of construction equipment fleets and data analysis. When measured and recorded, such results can be used along with decisionsupport tools for selection and utilization of construction equipment. The metrics for construction equipment evaluation as well as the tool for sustainable decisionmaking are developed based on readily available data from manufacturers or maintenance shops without a need for additional effort by contractors or government agencies for their adoption. The metrics developed and the decision support tool incorporate logical strategies of supply chain management for optimal selection of construction equipment for construction site while taking into account the availability, cost, and mobilization related constraints. The metrics and the model can benefit both the government agencies responsible for inspection of fleets and owners of construction companies in their decision-making processes related to environmental sustainability.

Web-based construction equipment fleet management system: cost-effective global and local allocation

Over the last two decades, construction contractors have been gradually making more investments in construction equipment to meet their needs associated with increasing volumes of construction projects. At present,from an operational perspective, almost all contractors pay more attention to maintaining their equipment fleets in well-sustained workable conditions and having a high accessibility of the necessary equipment pieces. However,such an approach alone is not enough to maintain an efficient and sustainable business. In particular, for largescale construction companies that operate in multiple sites in the U.S. or overseas, the problem extends to an optimal allocation of available equipment. Given the current state of the construction industry in the U.S., this problem can be solved by geographically locating equipment pieces and then wisely re-allocating them among projects. Identifying equipment pieces geographically is a relatively easy task.The difficulty arises when informed decision-making is required for equipment allocation among job sites. The actual allocation of equipment should be both economically feasible and technologically preferable. To help in informed decision-making, an optimization model is developed as a mixed integer program. This model is formed based on a previously successfully developed decision-support model for construction equipment selection. The proposed model incorporates logical strategies of supply chain management to optimally select construction equipment for any construction site while taking into account the costs, availability, and transportation-relatedissues as constraints. The model benefits those responsible for informed decision-making for construction equipment selection and allocation. It also benefits the owners of construction companies, owing to its cost-minimization objective.