scholarly journals Investigation of the prestressed beams and glass-window panels at a shopping centre

2019 ◽  
Vol 289 ◽  
pp. 10008
Author(s):  
Andreea-Terezia Mircea
Keyword(s):  
Interior Design ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Time Budget ◽  
Efficient Production ◽  
Commercial Building ◽  
Shopping Centre ◽  
Glass Panels ◽  
Cost Efficient ◽  
Concrete Elements

In today’s rapidly changing demands of commercial buildings, designers, manufacturers, contractors, and installers face the necessity to advance their methods, to improve techniques, and generally to stay competitive under all constraints of time, budget, codes and client desires. Building with precast concrete elements provides quick and cost-efficient production, along with flexible, independent interior design. The show-window of the investigated commercial building is divided into several glass panels. Having only upper and lower grip, the glass window panels with very tall heights, are subject to deformation. In order to resist, panels are provided with U-shaped profiles or/ and perimeter rails. The critical points are the glass panels’ support, so the ceiling and floor fastenings have to be very solid, as well as qualitatively superior designed and executed. This paper aims to highlight some relevant aspects regarding the investigation of the metal fixing system designed to connect show-window panels to prestressed concrete ceiling beams at a commercial building.

scholarly journals Dissecting cellobiose metabolic pathway and its application in biorefinery through consolidated bioprocessing in Myceliophthora thermophila

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Jingen Li ◽  
Shuying Gu ◽  
Zhen Zhao ◽  
Bingchen Chen ◽  
Qian Liu ◽  
...  
Keyword(s):  
Malic Acid ◽  
Plant Biomass ◽  
Consolidated Bioprocessing ◽  
Cellulase Activity ◽  
Industrial Applications ◽  
Efficient Production ◽  
Myceliophthora Thermophila ◽  
Final Strain ◽  
Cellobiose Metabolism ◽  
Cost Efficient

Abstract Background Lignocellulosic biomass has long been recognized as a potential sustainable source for industrial applications. The costs associated with conversion of plant biomass to fermentable sugar represent a significant barrier to the production of cost-competitive biochemicals. Consolidated bioprocessing (CBP) is considered a potential breakthrough for achieving cost-efficient production of biomass-based fuels and commodity chemicals. During the degradation of cellulose, cellobiose (major end-product of cellulase activity) is catabolized by hydrolytic and phosphorolytic pathways in cellulolytic organisms. However, the details of the two intracellular cellobiose metabolism pathways in cellulolytic fungi remain to be uncovered. Results Using the engineered malic acid production fungal strain JG207, we demonstrated that the hydrolytic pathway by β-glucosidase and the phosphorolytic pathway by phosphorylase are both used for intracellular cellobiose metabolism in Myceliophthora thermophila, and the yield of malic acid can benefit from the energy advantages of phosphorolytic cleavage. There were obvious differences in regulation of the two cellobiose catabolic pathways depending on whether M. thermophila JG207 was grown on cellobiose or Avicel. Disruption of Mtcpp in strain JG207 led to decreased production of malic acid under cellobiose conditions, while expression levels of all three intracellular β-glucosidase genes were significantly up-regulated to rescue the impairment of the phosphorolytic pathway under Avicel conditions. When the flux of the hydrolytic pathway was reduced, we found that β-glucosidase encoded by bgl1 was the dominant enzyme in the hydrolytic pathway and deletion of bgl1 resulted in significant enhancement of protein secretion but reduction of malate production. Combining comprehensive manipulation of both cellobiose utilization pathways and enhancement of cellobiose uptake by overexpression of a cellobiose transporter, the final strain JG412Δbgl2Δbgl3 produced up to 101.2 g/L and 77.4 g/L malic acid from cellobiose and Avicel, respectively, which corresponded to respective yields of 1.35 g/g and 1.03 g/g, representing significant improvement over the starting strain JG207. Conclusions This is the first report of detailed investigation of intracellular cellobiose catabolism in cellulolytic fungus M. thermophila. These results provide insights that can be applied to industrial fungi for production of biofuels and biochemicals from cellobiose and cellulose.

Chromate and amine contact allergies in workers manufacturing precast concrete elements

2016 ◽  
Vol 75 (6) ◽  
pp. 363-369 ◽  
Author(s):  
Martin Mowitz ◽  
Erik Zimerson ◽  
Inese Hauksson ◽  
Ann Pontén
Keyword(s):  
Precast Concrete ◽  
Concrete Elements

PCI Standard Design Practice Ref ACI 318-14

2021 ◽  
Author(s):  
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
Building Code ◽  
Design Practice ◽  
Structural Concrete ◽  
Design Engineers ◽  
Standard Design ◽  
Precast Prestressed Concrete ◽  
Consistent Approach ◽  
Code Provisions

Precast, prestressed concrete design is based on conformance with the provisions of the American Concrete Institute’s (ACI’s) Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14). In most cases, these provisions are followed explicitly. Occasionally, interpretation of some sections of ACI 318 is required to ensure quality is maintained in conjunction with the unique characteristics of precast and prestressed concrete fabrication, shipping, and erection. Members of the PCI Building Code Committee, along with other experienced precast concrete design engineers, have identified code provisions, detailed in this publication, that require clarification or interpretation. These design practices are followed by most precast concrete design engineers to produce safe, economical precast concrete structures and they provide a consistent approach for the designers and contractors.

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.

scholarly journals Modified mortar pad behavior in the transfer of compressive stresses

2016 ◽  
Vol 9 (3) ◽  
pp. 414-434
Author(s):  
J. D. Ditz ◽  
M. K. EL Debs ◽  
G. H. Siqueira
Keyword(s):  
Precast Concrete ◽  
Concrete Strength ◽  
Compressive Load ◽  
Stress Transfer ◽  
Compressive Stresses ◽  
Bonded Phase ◽  
Concrete Blocks ◽  
Load Tests ◽  
Styrene Butadiene ◽  
Concrete Elements

ABSTRACT This research aims to analyze the compressive stress transfer between precast concrete elements using cement mortar pads modified with polypropylene fibers, styrene-butadiene latex and heat-expanded vermiculite. The stress transfer analyses are performed interleaving a cementbearing pad between two concrete blocks, subjecting the entire specimen to different compressive load tests. The parameters analyzed in the tests are: surface roughness (using bosses on the bonded phase of different thicknesses), compressive strength with monotonic and cyclic loadings. The main results obtained in this study are: a) the presence of pad increased the strength in 24% for thicknesses of imperfections of 0.5 mm and approximately 12% for smooth faces blocks; b) gain of effectiveness of the bearing pad when the concrete strength was reduced; c) for cyclic loading, the bearing pad increased in 48% the connections strength.

scholarly journals SHEAR PERFORMANCE OF SPECIAL DRY JOINTS FOR PRECAST CONCRETE SEGMENTS

2021 ◽  
Vol 11 (1) ◽  
pp. 60-72
Author(s):  
Watanachai Smittakorn ◽  
Tosporn Prasertsri ◽  
Worapon Pattharakorn ◽  
Pitcha Jongvivatsakul
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
High Strength ◽  
Shear Capacity ◽  
Fiber Volume ◽  
Strength Concrete ◽  
Test Parameters ◽  
Ductile Shearing ◽  
Shear Performance ◽  
Normal Strength

The special dry joints for precast prestressed concrete segments are invented in this study toovercome the limitation of conventional dry joints. Eight specimens of special dry joints were madeand subjected to direct shear test. Test parameters comprise concrete compressive strength (normaland high strength concrete) and steel fiber volume added in the special dry joint (0%, 0.5%, and1.0%). Test results revealed that the inclusion of steel fibers remarkably enhanced the shear capacityand ductility index. Failure mode of specimens was changed from shearing off to concrete crackingaround shear key corners, defined as ductile shearing-off failure. Furthermore, the existing equationsfor predicting shear capacity of keyed joints were validated by the experimental results. Amongavailable equations from literatures, the Turmo’s equation yields better prediction of the shearcapacity for the special dry joint made with normal strength concrete.

scholarly journals perekonomian indonesa

2019 ◽  
Author(s):  
Pricyllia
Keyword(s):  
Sugar Industry ◽  
Raw Material ◽  
Efficient Production ◽  
Internal Conflicts ◽  
Beverage Industry ◽  
Self Sufficiency ◽  
Food And Beverage Industry ◽  
Food And Beverage ◽  
Cost Efficient ◽  
The Cost

The 1930s was the heyday of the Indonesian sugarindustry that is capable of exporting to manycountries and has become the country an exporterof sugar to two after Cuba, but the situation isreversed since 1967 in which Indonesia wouldimport sugar from Brazil, India, and Thailand inorder to meet the needs raw material consumptionand food and beverage industry. The resultsshowed that the cost of sugar production isvery uneconomical because of inefficiency thatstretches from the cultivation to processing inthe factory so difficult to obtain profit margins.Target and beyond sugar self-sufficiency can notbe achieved because highly regulated, there is nosynergy and tends to conflicts of interests amongministries or agencies, and internal conflicts oftenoccur between the sugar mill and the disharmonybetween sugarcane farmers by the sugar millofficials.In the competition of the sugar industry aremore stringent, in the era of the Asean EconomicCommunity, it means the level of efficiency of sugarfactories in the country need special attention,the same thing also applies to industrial users ofsugar, and sugar as a raw material componentscontribute to the creation of products food andbeverage efficient so as to compete with similarproducts from other countries. Observing howthe intense competition in the Asean EconomicCommunity is based on free trade, the yield ofsugar that’s a cost efficient production is veryimportant and urgent at this time, including workto improve the welfare of farmers.

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