A Case Study in Complex Concrete Construction in Australia:A Hybrid Approach of Hand and Machine

This paper describes and provides a critique of the design and implementation of the“scoops”-a set of bespoke multifunctioning architectural free-form elements that are a highlight of the new Soheil Abedian School of Architecture at Bond University,Australia,by the office of Sir Peter Cook and Gavin Robotham,CRAB(Cook Robotham Architecture Bureau,London).The development includes the transfer of analogue design processes into digital 3d modeling,which is then analyzed and rationalized via an exchange with consultants and procurement contractors.The complexity of the concrete works necessitated the use of digital fabrication to make their implementation affordable and within time constraints,with said complexity creating a variety of challenges for many aspects of the entire delivery team.The 3d model played a critical role in communicating intent and accuracy at all stages.The use of site-based craftsmanship combined with computer aided design and fabrication overlapped to realize the project.

Earthwork and the Strategies of Concrete Construction Technology Application in Building Construction

The pouring of mass concrete and earthwork account for a large proportion in building construction,which can play a decisive role in the quality of the building.Therefore,it is necessary to understand the technology of earthwork and concrete engineering in the process of building construction and propose reasonable application strategies.

Design and Construction Technology of Prefabricated Reinforced Concrete Slab Culverts

Compared with traditional cast-in-situ concrete slab culverts,prefabricated reinforced concrete slab culverts can be produced more quickly and has strong quality controllability,strong earthquake resistance,and repeatability.They will be the primary production method of slab culverts in the future.This article offers a comprehensive review of the design and construction technology associated with prefabricated reinforced concrete slab culverts.The objective is to provide a valuable reference for related enterprises,enhance the quality of design and construction in precast pile configuration,and,in turn,contribute to the advancement of construction projects within our country.

Research on the Reform of the Course“Reading of Concrete Structure Plan and Construction Drawings”Under the Background of“Promoting Teaching and Learning Through Competitions”

The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.

A Building Information Modeling-Life Cycle Cost Analysis Integrated Model to Enhance Decisions Related to the Selection of Construction Methods at the Conceptual Design Stage of Buildings

Life Cycle Cost Analysis (LCCA) provides a systematic approach to assess the total cost associated with owning, operating, and maintaining assets throughout their entire life. BIM empowers architects and designers to perform real-time evaluations to explore various design options. However, when integrated with LCCA, BIM provides a comprehensive economic perspective that helps stakeholders understand the long-term financial implications of design decisions. This study presents a methodology for developing a model that seamlessly integrates BIM and LCCA during the conceptual design stage of buildings. This integration allows for a comprehensive evaluation and analysis of the design process, ensuring that the development aligns with the principles of low carbon emissions by employing modular construction, 3D concrete printing methods, and different building design alternatives. The model considers the initial construction costs in addition to all the long-term operational, maintenance, and salvage values. It combines various tools and data through different modules, including energy analysis, Life Cycle Assessment (LCA), and Life Cycle Cost Analysis (LCCA) to execute a comprehensive assessment of the financial implications of a specific design option throughout the lifecycle of building projects. The development of the said model and its implementation involves the creation of a new plug-in for the BIM tool (i.e., Autodesk Revit) to enhance its functionalities and capabilities in forecasting the life-cycle costs of buildings in addition to generating associated cash flows, creating scenarios, and sensitivity analyses in an automatic manner. This model empowers designers to evaluate and justify their initial investments while designing and selecting potential construction methods for buildings, and enabling stakeholders to make informed decisions by assessing different design alternatives based on long-term financial considerations during the early stages of design.

Study on Durability of Recycled Aggregate Concrete in High-Temperature and Complex Environments

Recycled aggregate concrete refers to a new type of concrete material made by processing waste concrete materials through grading,crushing,and cleaning,and then mixing them with cement,water,and other materials in a certain gradation or proportion.This type of concrete is highly suitable for modern construction waste disposal and reuse and has been widely used in various construction projects.It can also be used as an environmentally friendly permeable brick material to promote the development of modern green buildings.However,practical applications have found that compared to ordinary concrete,the durability of this type of concrete is more susceptible to high-temperature and complex environments.Based on this,this paper conducts theoretical research on its durability in high-temperature and complex environments,including the current research status,existing problems,and application prospects of recycled aggregate concrete’s durability in such environments.It is hoped that this analysis can provide some reference for studying the influence of high-temperature and complex environments on recycled aggregate concrete and its subsequent application strategies.

Simplified full-depth precast concrete deck panel systems for accelerated bridge construction

A simplified full-depth precast concrete deck panel system for accelerating bridge construction （ABC） is introduced and a finite dement analysis （FEA） is con- ducted to investigate the static and dynamic responses of this conceptual deck system. The FEA results are compared to those of the traditional full-depth precast concrete deck panel system. The comparison results show that the mechanical behavior of the new deck system is different from that of the traditional deck system. The concrete decks in the new system act as two-way slabs, instead of the one-way slab in the traditional system. Meanwhile, the connections in both the longitudinal and transverse direc- tions may need to accommodate the negative moments. Compared to those in the traditional system, the longitu- dinal nominal stress at middle span increases a lot in the new deck system and the effective flange width varies significantly. In addition, the dynamic results show that the impact factor is influenced by the spacing of connections. Finally, some design concerns of the new deck system are proposed.

Influence of concrete differential aging time on the construction phases analysis of the Fenghua River Bridge

The Fenghua River Bridge is a major structure on the highway between Hengzhang and Guojiachi, which is to be built with a four-span prestress concrete (PC) box girder and symmetrical cantilever castings. In this paper, a finite element method (FEM) model is set up to study the effects of concrete differential aging time on the construction phases of the Fenghua River Bridge by calculating the vertical displacement of the folding segment of the middle span and the longitudinal bending moment of Pier 12#. In the model, the girders are classified into 150 changing sections based on the desgn scheme, and their construction is to be carried in 16 phases respectively to build 12 blocks connected by a side folding segment and a middle folding segment, covered with a second dead load and in completion for 20 years. It is found that the internal forces and deformations of the concrete structures at the aging time of 60 d are quite different from those of 0 d aging time while the behaviors of the structures of 120 d aging time is nearly the same as those of 60 d aging time― the differences are so small that can be neglected, suggesting that the creep develops obviously about one month after the cement is hardened and the development fades later on.

Influence of construction interfaces on dynamic characteristics of roller compacted concrete dams

To study the influence of construction interfaces on dynamic characteristics of roller compacted concrete dams(RCCDs),mechanical properties of construction interfaces are firstly analyzed. Then, the viscous-spring artificial boundary(VSAB) is adopted to simulate the radiation damping of their infinite foundations, and based on the Marc software, a simplified seismic motion input method is presented by the equivalent nodal loads. Finally, based on the practical engineering of a RCC gravity dam, effects of radiation damping and construction interfaces on the dynamic characteristics of dams are investigated in detail. Analysis results show that dynamic response of the RCC gravity dam significantly reduces about 25% when the radiation damping of infinite foundation is considered. Hot interfaces and the normal cold interfaces have little influence on the dynamic response of the RCC gravity dam.However, nonlinear fracture along the cold interfaces at the dam heel will occur under the designed earthquake if the cold interfaces are combined poorly. Therefore, to avoid the fractures along the construction interfaces under the potential super earthquakes,combination quality of the RCC layers should be significantly ensured.

BIM-based construction technologies for precast foamed lightweight concrete wallboards

To promote the visualisation and informatisation of the construction process of precast foamed lightweight concrete wallboards(PFLCWs),from the analysis of the construction requirements of PFLCWs,three key construction technologies based on building information modelling(BIM),namely,parameterised modelling for the PFLCW layout design,drawing generation to draw the PFLCW layout and quantity statistics for extracting PFLCW quantities,are proposed.Then,a reinforced concrete(RC)frame infilled with PFLCW is considered the test model to verify the feasibility of the aforementioned technologies.The results show that PFLCW layout design can be accomplished rapidly and visually using parameterised modelling technology.The PFLCW layout diagram can be generated directly using drawing generation technology.The proposed quantity statistics technology enables the automatic export of PFLCW bills of quantities.The built parameterised model helps construction workers rapidly and intuitively understand the specific layout details of PFLCWs.Moreover,the generated layout drawing and the bills of quantities based on the parameterised model can guide the production and on-site installation of PFLCWs.The research conclusions can serve as a practical guide and technical support for PFLCW engineering applications.

Optimization of construction machinery scheme of cast-in-situ concrete based on the improved scatter degree method

The basic requirement of mechanical construction of cast-in-situ concrete is that it could not only conduct quality qualification and safety production, but also achieve most economic benefits with less investment under the condition to meet the needs of project duration. Therefore, the selection of construction machinery scheme plays an important role. However, in the actual construction, it is usually that operators rely on their own experience and field conditions to determine the mechanics. Such a method is subjective and arbitrary, and it is not conducive to make the construction rationally. Considering the above reasons, an improved weight coefficient method was used to establish an estimation model to estimate the construction machinery scheme of cast-in-situ concrete, so as to make the procedure much rational.

Use of Masonry Construction &Demolition Waste in Concrete

Massive amounts of brick waste are obtained from demolition of old buildings and structures around the world. With the increased stress on sustainable construction, and environmentally friendly materials and greener concreting practices, a large proportion of such waste bricks are crushed and mixed with normal aggregates for use in concrete. The performance of concrete containing waste brick aggregates partially replacing normal aggregates have not been investigated for their performance. This paper covers investigations carried out on concrete with such aggregates obtained from demolition waste and mixed with varying proportions of normal aggregates to produce concrete. Two types of crushed brick aggregates were mixed with gravel in the ratios of 30:70 and 40:60 by weight and specimen were cast for investigations. Two w/c ratios were investigated. Various tests were carried out to assess the compressive strength of cubes and cylinders of mixed aggregates concrete along with f1exural strength, stress/strain behavior, moduli of elasticity, ultrasonic pulse velocity determination, densities, surface absorption, shrinkage and frost resistance. The values obtained from these tests were compared with the values of concrete with normal aggregates (gravel) with similar w/c ratios. While the strength tests and durability tests more or less gave satisfactory results however the larger moisture absorption by the waste brick aggregates reduces the frost resistance capacity somewhat thereby care needs to be exercised in using these mixes in regions/areas susceptible to frost.

Sustainable Construction—High Performance Concrete Containing Limestone Dust as Filler

Massive amounts of limestone waste are produced by the stone processing industry worldwide. Generally, it is believed that 60% to 70% of the stone is wasted in processing in the form of fragments, powder and slurry out of which around 30% is in the form of fine powder [1]. This waste has no beneficial usage and poses environmental hazards. Use of this waste product in the construction industry can largely reduce the amount of waste to be disposed off by the local municipalities in addition to reducing large burden on the environment. Some basic research on use of limestone dust as cement/ concrete filler?has?been carried out in the recent past but high strength/ high performance concretes have not been investigated yet [2] [3]. The concrete industry is among the largest consumer of raw materials worldwide and has been investigated for use of various types of waste materials like crushed brick, rice husk and straw ash as either aggregates for concrete or as partial cement substitutes. Use of limestone dust as filler material in concrete can consume a huge amount of this waste material which has to be disposed off otherwise, creating large burden on the environment. This experimental study aimed at evaluating the properties of high performance concretes made from Portland cement, natural aggregates and sand. Limestone dust was added by replacing sand in the percentages of 10% and 20%. Wide ranging investigations covering most aspects of mechanical behavior and permeability were carried out for various mixes for compressive strengths of 60?N/mm2, 80?N/mm2 and 100?N/mm2. Compressive strengths of concrete specimen with partial replacement of sand with 10% and 20% limestone dust as filler material for 60?N/mm2, 80N/mm2 and 100?N/mm2 were observed to be higher by about 4% to 12% than the control specimen. Flexural strengths were also observed to be higher by 12%?-?13%. Higher elastic moduli and reduced permeability were observed along with better sulphate and acid resistance. Better strengths and improved durability of such high-performance concretes make it a more acceptable material for major construction projects.

Predicting Compressive Strength of Recycled Concrete for Construction 3D Printing Based on Statistical Analysis of Various Neural Networks

Construction 3D printing is changing construction industry, but for its immaturity, there are still many problems to be solved. One of the major problems is to study materials for construction 3D printing. Because printed buildings are very different from traditional buildings, there are special requirements for printing materials. Based on environmental and cost considerations, the recycled concrete as printing material is a perfect choice. In order to study and develop the construction 3D printing materials, it is necessary to predict the properties of them. As one of the most effective artificial intelligence algorithms, artificial neural network can deal with multi-parameter and nonlinear problems, and it can provide useful reference to predict the performance of recycled concrete for 3D printing. However, since there are many types and parameters for neural network, it is difficult to select the optimal neural network with excellent prediction performance. In this paper, by comparing different types of neural networks and statistically analyzing the distribution of the root-mean-square error (RMSE) and the coefficient of determination (R2) of these neural networks, we can determine the best performance among four neural networks and finally select the suitable one to predict the performance of 3D printing concrete.

Influence of Aggregate Grain Size on the Formulation of Sand Concrete in the Construction Industry in Congo

The main objective of this study is to contribute to the optimization of the formulation of sand concretes and its valorisation according to natural sands from different quarries or extraction sites. Physical characteristics of natural sands have been determined and improved by the addition of crushing sand, taking into account the too fine elements of the sand. Four types of sand were used (Congo River, Djiri, Mfilou, crushed sand). The concrete formulations proposed from improved sands (30% crushed sand and 70% natural sand) reveal an increase in mechanical strength. Thus, it appeared that this improvement of the natural fine sands by the crushing sand has brought a clear increase in the maneuverability of the concretes and the physico-mechanical characteristics of nearly 50%, although this crushing sand has a sand equivalent value of less than 70%. These results augur well for the durability of structures in the construction industry in Congo.

An Experimental Study of Self-Compacting Concrete Made with Filler from Construction and Demolition Waste

This study evaluated the influence of the Portland cement replacement by 0, 5%, 10%, 15% and 20% of Construction and Demolition Waste (CDW) filler contents in the production of self-compacting concrete (SCC). The SCC mixtures were evaluated on fresh state by slump flow, J-ring, resistance of segregation, specific gravity, and on hardened state by compressive and splitting tensile strength, specific gravity, air voids and absorption rate. The results indicated that all SCC produced with CDW filler met the limits established at any level of substitution without changes of the w/c ratio or superplasticizer content. It was possible to verify that the presence of CDW filler, in substitution of cement, by volume, improves the resistance to segregation and up to 5% of CDW filler decreases the loss of fluidity with time as compared to reference. It was found that all SCC mixtures, at 28 days, had the average compressive strength above 50 MPa, without showing significant loss with up to 20% of CDW filler. For splitting tensile strength, SCC recycled mixtures reached up to 92.5% of the SCC used as reference. Absorption rate and air voids index of SCC recycled mixtures had a maximum increase of 1.60%Compared to the reference one. So, it is possible to conclude that the use of the CDW filler up to 20% in substitution of cement, by volume, is feasible for SCC production.

Bridge Falsework in Staged Construction of a Prestressed Concrete Beam Bridge

The formwork and falsework in the construction of twin ribbed slab decks on a multi-span ecological bridge for a dual carriageway are presented. The bridge is situated in a valley plain which is crossed by small rivers and was designed principally with the environment in mind. The bridge length is over 356 m, and the width of the decks is 11.5 m. For the bridge works, a simple conventional falsework system was chosen with steel frames for the supports and steel rolled beams for the decks. The formwork was constructed in solid timber and plywood as multiple-use panels. The falsework was designed in order to build the two 10-span bridge decks in stages. The decks are continuous cast-in-situ prestressed concrete twin rib with spans of 30 m, 34 m and 45 m. An individual falsework system was designed, which was easy to move transversally following completion of each stage for one deck. After finishing each stage, for the second deck, the falsework was dismantled and used again in the next construction fronts. An individual arrangement for the falsework along with timber pilings was used to cross the biggest river. The formwork timber panels were used several times in the multistage bridge construction. The adopted falsework system is very simple, but it allowed the speedy construction of the two decks where there were severe time constraints.

Analysis of Winter Concrete Construction in Water Conservation Project

The construction of water conservancy projects should commence during optimal atmospheric conditions and non-flood period to ensure completion before the flood season begin in summer.In most areas of Northern China,the temperature during winter remain at lower level,in which environmental factors play the most important role in the construction of water conservancy projects.In particular,low temperature directly affects the strength of concrete and delays its solidification,this highly affects the quality and progress of concrete construction.In order to overcome this barrier,better planning,for reasonable and effective construction techniques and targeted control measures should be adopted to reduce the adverse effects of low temperature to assure a strong and safe architecture.

Causes and Management of Concrete Cracks in Construction Engineering

In today’s comprehensive development of the domestic economy,China’s construction industry has reaped remarkable achievements.As a very important composition in the field of construction in China,the characteristics of concrete engineering itself determines that it is prone to encounter a variety of problems,the most frequent of which is various cracks.Cracks not only affect the aesthetics of the building,but also affect the durability and safety of the project.Considering these potential hazards,the causes of concrete cracks must be carefully analyzed to control and improve them in an effective way to ensure the safety and stability of concrete buildings.

Analysis on Construction Quality Control Technology of Reinforced Concrete Shear Wall Structure

In the process of continuous development of construction enterprises, new requirements have been put forward for construction projects. By strengthening the construction quality control of reinforced concrete shear wall structure, the construction level of reinforced concrete can be continuously improved, the construction quality can be guaranteed, and the construction project can be successfully completed, which is worthy of extensive application and promotion in construction enterprises, thus providing a broader development space for construction enterprises.