scholarly journals Innovative Lightweight Cold-Formed Steel-Concrete Composite Floor System – LWT-FLOOR project

2021 ◽  
Vol 1203 (3) ◽  
pp. 032078
Author(s):  
Ivan Lukačević ◽  
Ivan Ćurković ◽  
Andrea Rajić ◽  
Ivan Čudina
Keyword(s):  
Concrete Slab ◽  
Cost Effective ◽  
Steel Buildings ◽  
Steel Members ◽  
Floor Systems ◽  
New Construction ◽  
Building Components ◽  
Cold Formed Steel ◽  
Floor System ◽  
High Degree

Abstract To provide the foundations for economic and social prosperity, countries worldwide need to be making a term investment in their building assets. However, there is a lack of a systematic approach, such as manufacturing innovations, to maximize the values of building components and materials in its entire lifecycle. Steel-concrete composite floor systems are one of the most cost-effective construction systems for multi-storey steel buildings because they combine structural efficiency with the speed of construction. These advantages depend on the efficiency of combining steel and concrete structural elements to avoid their inherent disadvantages. This paper presents a solution that integrates state-of-the-art knowledge in new, fast and productive spot-welding technology and innovative cold-formed steel-concrete composite solutions. The solution proposes a new construction method as a combination of built- up cold-formed steel members and cast-in-place concrete slab. The proposed floor system offers key benefits in terms of a high degree of prefabrication, reusability and long spanning capability.

Theoretical Analysis of SSCC Floor System of through Truss High-Speed Railway Bridges

2011 ◽  
Vol 250-253 ◽  
pp. 1728-1733 ◽  
Author(s):  
Ye Zhi Zhang ◽  
Liang Chen
Keyword(s):  
High Speed ◽  
Concrete Slab ◽  
Axial Stress ◽  
Bending Moment ◽  
Bending Stress ◽  
Inertia Moment ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Floor Systems ◽  
Floor System

In SSCC floor systems the concrete slab is composite with both steel stringers and crossbeams or only with stringers. The horizontal bending of the crossbeams of SSCC floor systems is not ignorable. From the deformation conforming condition, theoretical formulas for SSCC floor systems of double-railway bridges with two stringers are developed. The factors which influence the horizontal bending of crossbeams are discussed. Some conclusions are obtained. When the width of the SSCC floor system is given, the main factors which influence the horizontal bending of the crossbeams are the axial stress of the lower chords, the distance between the side stringers and the lower chords, and the continuous length of SSCC floor system. Increasing the horizontal inertia moment of crossbeams almost cannot reduce the horizontal bending stress of crossbeams. A slight horizontal rotation of the lower joints such as 10-4 rad can release more than 3% crossbeam end horizontal bending moment.

scholarly journals Plate with holes as shear connector in cold formed steel composite beams

2019 ◽  
Vol 12 (3) ◽  
pp. 509-517
Author(s):  
O. P. AGUIAR ◽  
R. B. CALDAS ◽  
F. C. RODRIGUES ◽  
H. N .BELLEI
Keyword(s):  
Concrete Slab ◽  
Composite Beams ◽  
Shear Connector ◽  
Reinforced Concrete Slab ◽  
Relative Slip ◽  
Floor Systems ◽  
Composite Section ◽  
Support Area ◽  
Steel Composite ◽  
Cold Formed Steel

Abstract In search of an improved compatibility between cold-formed steel profiles and precast floor systems, this study proposes an alternative shear connector for cold-formed steel-concrete composite beams. This connector consists of a steel plate with holes placed longitudinally in the middle of the upper flange of the steel profile, aiming to maximize the support area for precast slabs during the assembly. The proposed solution was experimentally tested on I-beams under bending, composed by two cold-formed steel channels, connected to a reinforced concrete slab by the shear connector. The relative slip between the steel profile and concrete, vertical deflection of the beam, and strains at several locations of the composite section were measured. The results show that the proposed connector assures shear transfer at the interface of the composite section components and shows strength of the same magnitude as other commonly used connectors.

scholarly journals Design for Deconstruction: Futuristic Sustainable Solution for Structural Design

2020 ◽  
Vol 2 (1) ◽  
pp. 6-11
Author(s):  
Ali Al-Ghalib
Keyword(s):  
Raw Materials ◽  
Precast Concrete ◽  
Steel Structure ◽  
Embodied Energy ◽  
Steel Buildings ◽  
Design Standards ◽  
Embodied Carbon ◽  
Floor Systems ◽  
Floor System

The aim of this research is to investigate the sustainability of design for deconstruction on saving: natural raw materials, embodied energy and carbon emission of steel buildings. A methodology is devised to account for designed for upcoming reclaim at the early planning phase. The procedure is relied on PAS2050 method. A steel structure building of two bays of size (6m x 8m) and of 4m height is devoted as a case study to assess the methodology. In this case study, three different floor systems are suggested: composite steel deck, hollow core precast concrete planks, and demountable precast composite floor system. The reduced quantity of embodied carbon energy is estimated through considering the steel building. The calculation of embodied carbon of the three models is relied on records of the Inventory of Carbon and Energy (ICE). The results show that CO2 emissions from the building can be dropped around 50%, when design for deconstruction strategy is considered. Design standards and codes lack a little procedure to follow. Therefore, this study also outlines some helpful specifications, guidelines, and detailing of design for deconstruction of steel buildings.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

The Influence of Slab Concreting Sequence on a Continuous Composite Girder Bridge

2016 ◽  
Vol 691 ◽  
pp. 96-107
Author(s):  
Tomas J. Zivner ◽  
Rudolf B. Aroch ◽  
Michal M. Fabry
Keyword(s):  
Concrete Slab ◽  
Transverse Cross Section ◽  
Slab Thickness ◽  
Slab Width ◽  
Composite Girder ◽  
Steel Members ◽  
Composite Bridge ◽  
Bridge Girder ◽  
Girder Bridge ◽  
Main Girder

This paper deals with the slab concreting sequence and its influence on a composite steel and concrete continuous highway girder bridge. The bridge has a symmetrical composite two-girder structure with three spans of 60 m, 80 m, 60 m (i.e. a total length between abutments of 200.0 m). The horizontal alignment is straight. The top face of the deck is flat. The bridge is straight. The transverse cross-section of the slab is symmetrical with respect to the axis of the bridge. The total slab width is 12 m. The slab thickness varies from 0.4 m on main girders to 0.25 m at its free edges and 0.3075 m at its axis of symmetry. The center-to-center spacing between main girders is 7 m and the slab cantilever on either side is 2.5 m long. Every main girder has a constant depth of 2800 mm and the thicknesses of the upper and lower flanges are variable. The lower flange is 1200 mm wide whereas the upper flange is 1000 mm wide. The two main girders have transverse bracing at abutments and at internal supports and at regular intervals in every span. The material of concrete slab is C35/45 and of steel members S355. The on-site pouring of the concrete slab segments is performed by casting them in a selected order and is done after the launching of the steel two girder bridge. The paper presents several concreting sequences and their influence on the normal stresses and deflections of the composite bridge girder.

Full‐scale shake‐table tests on two unreinforced masonry cavity‐wall buildings: effect of an innovative timber retrofit

2021 ◽  
Author(s):  
Marco Miglietta ◽  
Nicolò Damiani ◽  
Gabriele Guerrini ◽  
Francesco Graziotti
Keyword(s):  
Seismic Vulnerability ◽  
Concrete Slab ◽  
Cost Effective ◽  
Unreinforced Masonry ◽  
Full Scale ◽  
Cavity Wall ◽  
Masonry Walls ◽  
Shake Table ◽  
Earthquake Excitation ◽  
Reinforced Concrete Slab

AbstractTwo full-scale building specimens were tested on the shake-table at the EUCENTRE Foundation laboratories in Pavia (Italy), to assess the effectiveness of an innovative timber retrofit solution, within a comprehensive research campaign on the seismic vulnerability of existing Dutch unreinforced masonry structures. The buildings represented the end-unit of a two-storey terraced house typical of the North-Eastern Netherlands, a region affected by induced seismicity over the last few decades. This building typology is particularly vulnerable to earthquake excitation due to lack of seismic details and irregular distribution of large openings in masonry walls. Both specimens were built with the same geometry. Their structural system consisted of cavity walls, with interior load-bearing calcium-silicate leaf and exterior clay veneer, and included a first-floor reinforced concrete slab, a second-floor timber framing, and a roof timber structure supported by masonry gables. A timber retrofit was designed and installed inside the second specimen, providing an innovative sustainable, light-weight, reversible, and cost-effective technique, which could be extensively applied to actual buildings. Timber frames were connected to the interior surface of the masonry walls and completed by oriented strands boards nailed to them. The second-floor timber diaphragm was stiffened and strengthened by a layer of oriented-strand boards, nailed to the existing joists and to additional blocking elements through the existing planks. These interventions resulted also in improved wall-to-diaphragm connections with the inner leaf at both floors, while steel ties were added between the cavity-wall leaves. The application of the retrofit system favored a global response of the building with increased lateral capacities of the masonry walls. This paper describes in detail the bare and retrofitted specimens, compares the experimental results obtained through similar incremental dynamic shake-table test protocols up to near-collapse conditions, and identifies damage states and damage limits associated with displacements and deformations.

scholarly journals Development of Optimal Design Method for Steel Double-Beam Floor System Considering Rotational Constraints

2021 ◽  
Vol 11 (7) ◽  
pp. 3266
Author(s):  
Insub Choi ◽  
Dongwon Kim ◽  
Junhee Kim
Keyword(s):  
Optimal Design ◽  
Design Process ◽  
Design Method ◽  
Steel Beams ◽  
High Gravity ◽  
Double Beam ◽  
Iterative Analysis ◽  
Floor Systems ◽  
Optimal Design Method ◽  
Floor System

Under high gravity loads, steel double-beam floor systems need to be reinforced by beam-end concrete panels to reduce the material quantity since rotational constraints from the concrete panel can decrease the moment demand by inducing a negative moment at the ends of the beams. However, the optimal design process for the material quantity of steel beams requires a time-consuming iterative analysis for the entire floor system while especially keeping in consideration the rotational constraints in composite connections between the concrete panel and steel beams. This study aimed to develop an optimal design method with the LM (Length-Moment) index for the steel double-beam floor system to minimize material quantity without the iterative design process. The LM index is an indicator that can select a minimum cross-section of the steel beams in consideration of the flexural strength by lateral-torsional buckling. To verify the proposed design method, the material quantities between the proposed and code-based design methods were compared at various gravity loads. The proposed design method successfully optimized the material quantity of the steel double-beam floor systems without the iterative analysis by simply choosing the LM index of the steel beams that can minimize objective function while satisfying the safety-related constraint conditions. In particular, under the high gravity loads, the proposed design method was superb at providing a quantity-optimized design option. Thus, the proposed optimal design method can be an alternative for designing the steel double-beam floor system.

scholarly journals Formulation and Mathematical Optimization of Controlled Release Calcium Alginate Micro Pellets of Frusemide

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Amitava Ghosh ◽  
Prithviraj Chakraborty
Keyword(s):  
Sodium Alginate ◽  
Calcium Alginate ◽  
Mathematical Optimization ◽  
Extended Period ◽  
Cost Effective ◽  
Polynomial Equation ◽  
Chronic Hypertension ◽  
Order Polynomial ◽  
High Degree

Objective. Frusemide loaded calcium alginate micropellets, an oral microparticulate delivery system, was statistically optimized exhibiting prolonged therapeutic action minimizing its adverse effects.Methods. Ionotropic Gelation technique was adopted employing 32Factorial designs and keeping the entire process free from organic solvents. Physicochemical and the release characteristics of the prepared formulations were studied, keeping variations only in sodium alginate (primary polymer) and Acrycoat E30D (copolymer) dispersion.Result. Sodium alginate was predominant over Acrycoat E30D in all batches. Nonadditives or interaction was observed to be insignificant. Multiple regressions produced second-order polynomial equation, and the predictive results obtained were validated with high degree of correlation. Thein vivostudy applauded that optimized calcium alginate micropellets of frusemide can produce a much greater diuretic effect over an extended period of 24 hours.Conclusion. This study reveals that the potential of a single dose of the mathematically optimized micro pellets of frusemide formulation is sufficient in the management of peripheral edema and ascites in congestive heart failure and as well in the treatment of chronic hypertension, leading to better patient compliance, and can be produced with minimum experimentation and time, proving far more cost-effective formulation than the conventional methods of formulating dosage forms.

scholarly journals Intersecting Residential and Transportation CO2 Emissions: Metropolitan Climate Change Programs in the Age of Trump

2017 ◽  
Vol 39 (2) ◽  
pp. 206-226 ◽  
Author(s):  
John D. Landis ◽  
David Hsu ◽  
Erick Guerra
Keyword(s):  
Energy Conservation ◽  
Fixed Ratio ◽  
Cost Effective ◽  
Scale Efficiency ◽  
Diversion Programs ◽  
Residential Energy ◽  
Past Performance ◽  
Compact Growth ◽  
New Construction ◽  
Effective Cost

This article uses a series of fixed-ratio projections and scenarios to explore the potential for local residential energy conservation mandates and compact growth programs to reduce locally based CO2 emissions in eleven representative US metropolitan areas. Averaged across all eleven metros, residential energy conservation mandates could reduce residential CO2 emissions in 2030 by an average of 30 percent over and above 2010 levels. In terms of implementation, residential conservation standards were found to be goal-effective, cost-effective, scale-effective, and in the case of new construction standards, reasonably resistant to local political pushback. Local compact growth programs do not perform as well. If accompanied by aggressive efforts to get drivers out of their cars, compact growth programs could reduce auto-based 2030 CO2 emissions by as much as 25 percent over and above any emissions reductions attributable to higher fuel economy standards. Unaccompanied by modal diversion programs, the stand-alone potential for local compact growth programs to reduce auto-based CO2 emissions falls into a more modest range of 0 to 7 percent depending on the metropolitan area. Based on past performance, local compact growth programs are also likely to have problems in terms of their goal- and scale-efficiency, and their potential to incur political pushback.

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