scholarly journals The application efficiency of precast monolithic frame systems in civil engineering

Vestnik MGSU ◽  
2021 ◽  
pp. 1493-1507
Author(s):  
Mariia D. Strelkova ◽  
Ksenia I. Strelets ◽  
Victor Z. Velichkin ◽  
Marina V. Petrochenko
Keyword(s):  
Carbon Dioxide ◽  
Precast Concrete ◽  
Weighted Average ◽  
Residential Building ◽  
Production Costs ◽  
Frame Structure ◽  
Partial Replacement ◽  
Construction Time ◽  
Frame Systems ◽  
Optimal Type

Introduction. The partial replacement of cast-in-situ concrete with precast concrete in the residential construction sector allows to reduce construction time and cost, increase labour productivity and cut CO2 emissions. Combinations of prefabricated and monolithic elements in precast monolithic frames are presented; they encompass 6 different structural options of precast monolithic frames and 2 types of monolithic frames. The co-authors compare production costs and integrated labor intensity for all frame design options, construction periods per 1,000 m3 of a residential building for various structural options of the frame, and assess potential reduction in carbon dioxide emissions due to a change in the amount of precast reinforced concrete in the building frame structure. Materials and methods. The co-authors have developed a method that employs weighted average to identify the optimal type of a precast monolithic frame. The method takes account of such factors as production costs, integrated labour intensity, construction time and reduction in carbon dioxide gas emissions (in per centum) per 1,000 m3 of the frame structure. Results. The optimal structure of a precast monolithic frame was selected and calculated using weighted average. Weighted average was used to identify the most effective structural frame. The calculation results have shown that ARKOS precast monolithic frame with precast columns is the leader in terms of weighted average; it best suits the construction of a residential building. If we consider each of the selected indicators separately, RECON frame with precast floors is to be selected; however, RECON is inferior to ARKOS in terms of weighted average due to different values of the weight coefficients attached to each of the assessment criteria. Conclusions. The co-authors have proven the efficiency of precast monolithic frame systems in comparison with monolithic frames if applied to construct a residential building. The proposed method was employed to select the optimal type of frame.

scholarly journals Barriers to Adoption of Precast Concrete Construction in Buildings

2021 ◽  
Author(s):  
Alan Verghese Ittyeipe ◽  
Anu V. Thomas
Keyword(s):  
Precast Concrete ◽  
Health And Safety ◽  
Residential Building ◽  
Developed Countries ◽  
Barriers To Adoption ◽  
Construction Time ◽  
Concrete Construction ◽  
Building Projects ◽  
High Rise ◽  
Housing Shortages

The increasing demands for housing the burgeoning urban population in developing countries like India has impelled the need to shift to mechanised construction practices like Precast Concrete Construction (PCCon) for faster supply of projects. PCCon has been successfully implemented in developed countries to meet the once prevalent housing shortages and is still being adopted extensively in high rise residential building projects in these countries. PCCon offers several benefits compared to cast in situ construction practices such as reduced construction time, time and cost certainty, improved quality control and improved health and safety. PCCon also promotes environment friendly construction, addresses shortage of skills and results in minimisation of life cycle costs.

Shear connection between precast concrete bridge segments built with thin-walled elements

2021 ◽  
Author(s):  
Tobias Huber ◽  
Stephan Fasching ◽  
Johann Kollegger
Keyword(s):  
Precast Concrete ◽  
Deformation Behaviour ◽  
Lateral Force ◽  
Test Results ◽  
Construction Time ◽  
Shear Connection ◽  
Force Transfer ◽  
Strength And Deformation ◽  
Thin Walled ◽  
Segmental Bridge

<p>Segmental bridge construction combines the advantages of prefabrication, for example the reduction of construction time and very high product quality, with those of common bridge erecting methods. Short precast segments are assembled and prestressed to form the complete superstructure. New methods divide these segments into prefabricated elements to create new lighter versions of the segments. For this to work, new joint types must be developed which can ensure the force transfer between the segments. In this paper, several methods, including a new concept for joining thin-walled pre-fabricated elements, are described. Push-off tests with a constant lateral force were carried out to assess the shear strength and deformation behaviour. The main parameters were the joint type (wet joints: plain, grooved, keyed; dry joints), the mortar type, and the level of lateral force. In this paper, the test results are presented and recalculations with a design code are shown.</p>

Experimental investigation of seismic performance of a novel isostatic frame-cladding system

2022 ◽  
pp. 136943322110572
Author(s):  
Xun Chong ◽  
Pu Huo ◽  
Linlin Xie ◽  
Qing Jiang ◽  
Linbing Hou ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Damage Evolution ◽  
Failure Modes ◽  
Static Load ◽  
Precast Concrete ◽  
Frame Structure ◽  
Deformation Capacity ◽  
Load Bearing Capacity ◽  
Cladding Panels ◽  
Energy Dissipation Capacity

A new connection measure between the precast concrete (PC) cladding panel and PC frame structure is proposed to realize a new kind of isostatic frame-cladding system. Three full-scale PC wall-frame substructures were tested under the quasi-static load. These substructures included a bare wall-frame specimen, a specimen with a cladding panel that has no opening, and a specimen with a cladding panel that has an opening in it. The damage evolution, failure mode, load-bearing capacity, deformation capacity, and energy dissipation capacity of three specimens were compared. The results indicated that the motions of the cladding panels and the main structures were uncoupled through the relative clearance of the bottom connections, and three specimens exhibited approximately identical failure modes and seismic performance. Thus, the reliability of this new isostatic system was validated.

scholarly journals Experimental Study of a New Precast Prestressed Concrete Joint

2018 ◽  
Vol 8 (10) ◽  
pp. 1871 ◽  
Author(s):  
Xueyuan Yan ◽  
Suguo Wang ◽  
Canling Huang ◽  
Ai Qi ◽  
Chao Hong
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Frame Structure ◽  
Loading Test ◽  
Concrete Frame ◽  
Concrete Joints ◽  
Precast Prestressed Concrete

Precast monolithic structures are increasingly applied in construction. Such a structure has a performance somewhere between that of a pure precast structure and that of a cast-in-place structure. A precast concrete frame structure is one of the most common prefabricated structural systems. The post-pouring joint is important for controlling the seismic performance of the entire precast monolithic frame structure. This paper investigated the joints of a precast prestressed concrete frame structure. A reversed cyclic loading test was carried out on two precast prestressed concrete beam–column joints that were fabricated with two different concrete strengths in the keyway area. This testing was also performed on a cast-in-place reinforced concrete joint for comparison. The phenomena such as joint crack development, yielding, and ultimate damage were observed, and the seismic performance of the proposed precast prestressed concrete joint was determined. The results showed that the precast prestressed concrete joint and the cast-in-place joint had a similar failure mode. The stiffness, bearing capacity, ductility, and energy dissipation were comparable. The hysteresis curves were full and showed that the joints had good energy dissipation. The presence of prestressing tendons limited the development of cracks in the precast beams. The concrete strength of the keyway area had little effect on the seismic performance of the precast prestressed concrete joints. The precast prestressed concrete joints had a seismic performance that was comparable to the equivalent monolithic system.

Abstract 348: Impact of Low and High Partial Pressure of Carbon Dioxide on Neuron Specific Enolase Derived from Serum and Cerebrospinal Fluid in Patients Who Underwent Targeted Temperature Management After Out-of-hospital Cardiac Arrest: A Retrospective Study

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Changshin Kang
Keyword(s):  
Carbon Dioxide ◽  
Cerebrospinal Fluid ◽  
Cardiac Arrest ◽  
Retrospective Study ◽  
Neuron Specific Enolase ◽  
Weighted Average ◽  
Carbon Dioxide Tension ◽  
Spontaneous Circulation ◽  
Temperature Management ◽  
Multi Centre Study

Aim: In a previous study, low and high-normal arterial carbon dioxide tension (PaCO 2 ) were not associated with serum neuron specific enolase (NSE) in cardiac arrest survivors. We assessed the effect of PaCO 2 on NSE in cerebrospinal fluid (CSF) and serum. Methods: This was a retrospective study. PaCO 2 for the first 24 h was analysed in four means, qualitative exposure state (qES), time-weighted average (TWA), median, and minimum-maximum (Min-Max). These subgroups were divided into low (LCO 2 ) and high PaCO 2 (HCO 2 ) groups defined as PaCO 2 ≤35.3 and PaCO 2 >43.5 mmHg, respectively. NSE was measured at 24, 48, and 72 h (sNSE 24,48,72 and cNSE 24,48,72 ) from return of spontaneous circulation (ROSC). The primary outcome was the association between PaCO 2 and the NSE measured at 24 h after ROSC. Results: Forty-two subjects (male, 33; 78.6%) were included in total cohort. PaCO 2 in TWA subgroup was associated with cNSE 24,48,72 , while PaCO 2 in the other subgroup were only associated with cNSE 24 . PaCO 2 and cNSE in qES subgroup showed good correlation (r= -0.61; p< 0.01), and in TWA, Median, and Min-Max subgroup showed moderate correlations (r= -0.57, r= -0.48, and r= -0.60; p< 0.01). Contrastively, sNSE was not associated and correlated with PaCO 2 in all analysis. Poor neurological outcome in LCO 2 was significantly higher than HCO 2 in qES, TWA, and Median subgroups ( p< 0.01, p< 0.01, and p= 0.02). Conclusion: Association was found between NSE and PaCO 2 using CSF, despite including normocapnic ranges; TWA of PaCO 2 may be most strongly associated with CSF NSE levels. A prospective, multi-centre study is required to confirm our results.

scholarly journals Evaluation of Gas Emissions, Energy Consumption and Production Costs of Warm Mix Asphalt (WMA) Involving Natural Zeolite and Reclaimed Asphalt Pavement (RAP)

2020 ◽  
Vol 12 (16) ◽  
pp. 6410
Author(s):  
Alejandra T. Calabi-Floody ◽  
Gonzalo A. Valdés-Vidal ◽  
Elsa Sanchez-Alonso ◽  
Luis A. Mardones-Parra
Keyword(s):  
Energy Consumption ◽  
Fuel Consumption ◽  
Natural Zeolite ◽  
Asphalt Pavement ◽  
Warm Mix Asphalt ◽  
Production Costs ◽  
Partial Replacement ◽  
Reclaimed Asphalt Pavement ◽  
Gas Emissions ◽  
Reclaimed Asphalt

Asphalt mixture is the most widely used material in road construction, and the industry is developing more sustainable technologies. Warm mix asphalt (WMA) is a promising alternative as it saves energy, reduces fuel consumption and generates fewer gas and fume emissions, while maintaining a similar performance to hot mix asphalt (HMA). This paper presents an evaluation of the gas emissions at laboratory scale, as well as the energy consumption and production costs, of five types of WMA with the addition of natural zeolite. The control mixture was a HMA manufactured at 155 °C. The mixtures evaluated were two WMA manufactured at 135 °C with 0.3% and 0.6% natural zeolite, and three WMA with partial replacement of raw materials by 10%, 20% and 30% of reclaimed asphalt pavement (RAP); these mixtures, called WMA–RAP, were manufactured at 125 °C, 135 °C and 145 °C, respectively. The results indicated that all the mixtures evaluated reduced CO and CO2 emissions by 2–6% and 17–37%, respectively. The energy consumption presented a 13% decrease. In the current situation, the production costs for WMA with 0.3 and 0.6% natural zeolite are slightly higher than the control mixture, because the saving achieved in fuel consumption is lower than the current cost of the additive. On the other hand, WMA manufactured with the addition of natural zeolite and RAP could produce cost savings of up to 25%, depending on the amounts of RAP and natural zeolite used.

scholarly journals Structural Model for Fibre-Reinforced Precast Concrete Sandwich Panels

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Luis Segura-Castillo ◽  
Nicolás García ◽  
Iliana Rodríguez Viacava ◽  
Gemma Rodríguez de Sensale
Keyword(s):  
Structural Model ◽  
Precast Concrete ◽  
Cost Savings ◽  
Production Costs ◽  
Practical Case ◽  
Analysis Model ◽  
Steel Mesh ◽  
Tensile Forces ◽  
Precast Concrete Sandwich Panel ◽  
Precast Elements

Fibre-reinforced concrete (FRC) has been used in numerous types of precast elements around the world, as has been shown that reductions in production costs and time can be obtained; however, there is little experience of this material in Uruguay. Therefore, our study analysed the feasibility of its utilisation in this country. This paper reports on the development of a simple analysis model that is useful for the design of FRC precast elements. The model efficiency was evaluated through its application to a practical case study—vertical precast concrete sandwich panel systems tested by bending. Three different types of reinforcement were analysed: synthetic fibres, metal fibres, and steel mesh. With the developed model, the cost-efficiency of different panel geometries and amounts of reinforcement were evaluated. The model allowed consideration of the contribution of the fibres to withstand internal tensile forces of the panels and therefore be able to substitute for the steel mesh in the panel wythes. It was found that it was possible to optimise panel reinforcement and geometry, thereby reducing wythe thickness. Besides the reduction in production time, it was possible to achieve cost savings of up to 10% by replacing steel mesh with fibres and of more than 20% if the geometry was also modified.

Thermoeconomic Analysis of a Gas Turbine Plant With Fuel Decarbonization and Carbon Dioxide Sequestration

2002 ◽  
Author(s):  
M. Bozzolo ◽  
M. Brandani ◽  
A. Traverso ◽  
A. F. Massardo
Keyword(s):  
Carbon Dioxide ◽  
Gas Turbine ◽  
Capital Investment ◽  
Carbon Tax ◽  
Carbon Dioxide Sequestration ◽  
Production Costs ◽  
Fuel Gas ◽  
Total Capital ◽  
Total Capital Investment ◽  
Water Gas

In this paper the thermoeconomic analysis of gas turbine plants with fuel decarbonisation and carbon dioxide sequestration is presented. The study focuses on the amine (MEA) decarbonisation plant lay-out and design, also providing economic data about the total capital investment costs of the plant. The system is fuelled with methane that is chemically treated through a partial oxidation and a water-gas shift reactor. CO2 is captured from the resulting gas mixture, using an absorbing solution of water and MEA that is continuously re-circulated through an absorption tower and a regeneration tower: the decarbonised fuel gas is afterwards burned in the gas turbine. The heat required by CO2 sequestration is mainly recovered from the gas turbine exhausts and partially from the fuel treatment section. The reduction in efficiency and the increase in energy production costs due to fuel amine decarbonisation is evaluated and discussed for different gas turbine sizes and technologies (microturbine, small size regenerated, aeroderivative, heavy duty). The necessary level of carbon tax for a conventional plant without a fuel decarbonisation section is calculated and a comparison with the Carbon Exergy Tax procedure is carried out, showing the good agreement of the results.

Literature Review of Precast Concrete Frame Structures in Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 3-6
Author(s):  
Ke Wei Ding ◽  
Xiang Zhang
Keyword(s):  
Literature Review ◽  
Seismic Behavior ◽  
Civil Engineering ◽  
Precast Concrete ◽  
Engineering Application ◽  
Frame Structure ◽  
Frame Structures ◽  
Structure System ◽  
Concrete Frame ◽  
Performance Research

As construction industrialization is springing up in our country, precast concrete frame structure,as a result,has been developing rapidly. Based on a host of articles about precast concrete frame structure system at home and abroad,it,in this paper,summarized and prospected the latest stress performance research of precast concrete frame structure and up-to-date engineering application. Further more, total assembled node and seismic behavior of precast concrete frame structure is also pointed out as what is needed to study in the future.

Evolution of Design Code Requirements for Exterior Elements and Connections

2005 ◽  
Vol 21 (1) ◽  
pp. 213-224 ◽  
Author(s):  
Brian J. Sielaff ◽  
Richard J. Nielsen ◽  
Edwin R. Schmeckpeper
Keyword(s):  
Precast Concrete ◽  
Lateral Force ◽  
Frame Structure ◽  
Building Code ◽  
Seismic Zone ◽  
Seismic Rehabilitation ◽  
Story Drift ◽  
Moment Resisting ◽  
Design Requirements ◽  
Steel Frame Structure

Seismic design requirements for precast concrete cladding panel connections have evolved significantly over the past fifty years. This paper summarizes the pertinent requirements from the Uniform Building Code from 1967 to 1997, and the International Building Code 2000. A hypothetical design illustrates how emphasis in the code has evolved for both lateral force requirements and story drift displacement requirements arriving at a balance of moderate lateral force and displacement requirements. The numerical results are based on a hypothetical case of panel connections for a ten-story moment-resisting steel frame structure built in seismic Zone 4. This historical summary is of value to designers who deal with the seismic rehabilitation of precast panel connections.

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