Exterior Wall Panels Research Articles

Optimization of Energy Efficiency of Residential Buildings Built of Bearing Three-Dimensional Blocks

The article discusses the analysis of volume-block housing construction from the point of view of thermal protection of buildings. The results of full-scale tests on quality control of heat-protective properties of external walls and heat-accumulating ability of the object, on control of air permeability of the enclosing structures are presented. The multiplicity of air exchange in buildings made of volumetric blocks has been established. The estimation of the reduced heat transfer resistance of the exterior wall panel in natural conditions is made. A method of increasing the energy efficiency of houses of this type is proposed. During instrumental examination of the building, the method of complex thermal imaging control combining the advantages of the thermal imaging control method, making it possible to contactless record the distribution of radiation temperature on the surface in the field of view of the thermal imaging camera and high accuracy of contact methods for measuring temperature and heat fluxes, was used. Conducting thermal imaging of the outer and inner surfaces of the enclosing structure, we obtain the thermogram: two-dimensional images of the examined surfaces, where the color corresponds to the temperature value determined by the temperature scale of the thermogram. This thermogram makes it possible to conduct a detailed and reliable analysis of the state of the structure and its behavior in dynamics.

Carbon dynamics of paper, engineered wood products and bamboo in landfills: evidence from reactor studies

BackgroundThere has been growing interest in the development of waste-specific decay factors for estimation of greenhouse gas emissions from landfills in national greenhouse gas inventories. Although engineered wood products (EWPs) and paper represent a substantial component of the solid waste stream, there is limited information available on their carbon dynamics in landfills. The objective of this study was to determine the extent of carbon loss for EWPs and paper products commonly used in Australia. Experiments were conducted under laboratory conditions designed to simulate optimal anaerobic biodegradation in a landfill.ResultsMethane generation rates over incubations of 307–677 days ranged from zero for medium-density fibreboard (MDF) to 326 mL CH4 g−1 for copy paper. Carbon losses for particleboard and MDF ranged from 0.7 to 1.6%, consistent with previous estimates. Carbon loss for the exterior wall panel product (2.8%) was consistent with the expected value for blackbutt, the main wood type used in its manufacture. Carbon loss for bamboo (11.4%) was significantly higher than for EWPs. Carbon losses for the three types of copy paper tested ranged from 72.4 to 82.5%, and were significantly higher than for cardboard (27.3–43.8%). Cardboard that had been buried in landfill for 20 years had a carbon loss of 27.3%—indicating that environmental conditions in the landfill did not support complete decomposition of the available carbon. Thus carbon losses for paper products as measured in bioreactors clearly overestimate those in actual landfills. Carbon losses, as estimated by gas generation, were on average lower than those derived by mass balance. The low carbon loss for particleboard and MDF is consistent with carbon loss for Australian wood types described in previous studies. A factor for carbon loss for combined EWPs and wood in landfills in Australia of 1.3% and for paper of 48% is proposed.ConclusionsThe new suggested combined decay factor for wood and EWPs represents a significant reduction from the current factor used in the Australian greenhouse gas inventory; whereas the suggested decay factor for paper is similar to the current decay factor. Our results improve current understanding of the carbon dynamics of harvested wood products, and allow more refined estimates of methane emissions from landfills.

Processing of exterior light concrete wall panels

The characteristics of wall panels, the facing element of which is porous concrete, are given. For exterior wall panels, laboratory suggested the exposed porous concrete of grades B7,5 and B10 based on white and grey cements M400. As aggregates, one uses limestone and granite mined in the corresponding quarry. Air-entangling additives are applied in concrete manufacturing, due to which placeability of concrete mix is improved and volumetric weight of concrete is reduced. In its turn, it allowed reducing water absorption and enhancing freeze resistance of products. Presence of fine-splitted air in formation of closed pores (pore forming) improves the structure of exposed concrete, bringing its properties closer to the ones of porous claydite-concrete as the essential material of exterior wall panel. Homogeneity of concrete by durability came to 0,70 with variability coefficient equal to 0,11, what exceeds regulatory requirements. Its factory features and way of production are indicated. The range of application and the actual cost of such panels are identified.

Exterior prefabricated panelized walls platform optimization

Abstract Panelized wall system (PWS) is an effective offsite prefabrication approach that provides higher flexibility and customization power compared to modular construction. Product platform is an industrial engineering approach that can help in managing the panels' layout and component proliferation in the effort to comply with varying design requirements. Accordingly, this paper presents the development, implementation, and validation of a new exterior panelized walls platform optimization (EPWPO) model that optimizes the tradeoff between minimizing the total fabrication cost of the panels and minimizing the resulting design deviation from enforcing common platform designs for the panels. Two new metrics were developed to quantify the two conflicting objectives of panel platform design: total fabrication cost ( TFC ) and design deviation index (DDI). New computational algorithms were developed to automate the functions of panel elements geometry manipulation, structural analysis, and structural design in conjunction with the optimization process. The performance of the EPWPO model was illustrated using an application example of the fabrication of the exterior wall panels of a public school. Two analyses were performed to investigate the dependence of the model results on the platform configuration input and the degree of wall length tolerances.

The potential for cascading wood from demolished buildings: the condition of recovered wood through a case study in Finland

The aim of this study was to understand the current situation of wooden C&DW in Finland through a survey conducted on the demolition of a case study building. The results revealed that the extent of damage to the recovered wood is more dependent on the location than on the dimension. The condition of recovered wood from an integrated unit part (e.g. exterior wall panel) tended to be worse due to the attachment of other materials (e.g. insulation, plastic sheet), while recovered wood in better condition could be obtained from independent parts (e.g. roof truss, exterior cladding). These results would indicate that the cascading potential for recovered wood should be discussed in terms of both cross-section and location. In particular, the wood used as exterior cladding seems to have good potential for cascading and this could help extend the target for cascading wood from purely wooden building to other buildings.

Application of Styrofoam in the Elements of Building Constructions

The article presents the possibilities for the contemporary application of Styrofoam in the elements of building structures. Having in mind that Styrofoam belongs to a group of highly flammable materials, 5 % of combustion retarder - so called "retardant" - needs to be added to the amount when produced for structural building elements. That kind of Styrofoam is called "self-extinguishing" contrary to "normal" that does not contain that substance. The Article also shows the way in which building elements are constructed (external and interfloor construction), made out of Styrofoam using "Plastbau" technology. A possibility to use exterior wall panels ‘Plastbau’ under weather conditions of Saint-Petersburg has been considered. Temperature distribution along a wall’s section as well as a heat flow going through a building enclosure ‘Plastbau’ have been also analyzed herein.

Blast Performance of Single-Span Precast Concrete Sandwich Wall Panels

AbstractA research program was conducted to assess the capability of conventional non-load-bearing insulated precast concrete exterior wall panels to withstand blast loadings. Typical construction details from the tilt-up and prestressed concrete industries were examined. The sensitivity of insulation type, reinforcement, foam thickness, and shear tie type on the flexural resistance was assessed. Forty-two single-span static experiments were conducted on 14 different panel designs. From the results of these experiments, resistance functions and deformation limits for insulated concrete sandwich panels were determined. The resistance functions were used to develop predictive dynamic models for panels subjected to blast demands. The models were found to be accurate in comparison to measurements from four full-scale blast detonations. The findings of the research indicate that both prestressed and non-prestressed insulated concrete wall panels meet current rotational limits defined by the U.S. Army Corps of ...

Improved fire resistant performance of load bearing cold-formed steel interior and exterior wall systems

In order to improve the fire performance of load-bearing CFS wall systems for applications in mid-rise buildings, different panels and external insulation were examined in this paper. Experiments on six full-scale CFS wall specimens were performed in which the insulation material of aluminum silicate wool was located outside the CFS frame and sandwiched between two layers of boards on the fire side instead of being placed in the cavity. Five types of panels were involved in the experiments, including gypsum plasterboard, bolivian magnesium board, oriented standard boards (OSB), autoclaved lightweight concrete (ALC) boards and rock wool boards. The results showed a noticeable reduction of heat transfer to the surface of steel stud and a considerable improvement of fire performance of CFS walls by using aluminum silicate wool as external insulation. For CFS walls with aluminum silicate wool as external insulation on fire side, gypsum plasterboard as face layer and bolivian magnesium board as base layer on both sides, different load ratios may result in different failure modes, and the fire resistant time can be more than 150min when the load ratio was less than 0.65. It was also demonstrated that the fire performance of CFS wall systems lined with bolivian magnesium board or ALC boards were superior to those lined with gypsum plasterboard and OSB. Therefore, bolivian magnesium board may be recommended to replace gypsum plasterboards as the base layer and ALC board may be used to replace OSB as exterior wall panels of CFS wall systems for applications in mid-rise buildings.

Composite Steel Stud Blast Panel Design and Experimental Testing

Based on Federal Aviation Authority (FAA) requirements, project specific blast loads are determined for the design of a new airport traffic control tower. These blast loads must be resisted by exterior wall panels on the control tower, protecting building occupants from intentional explosives attack scenarios. Such blast resistant walls are typically constructed of thick reinforced concrete panels or composite steel plate and rolled sections, as conventional building cladding systems have relatively low blast resistance. While these more robust design approaches are valid, the additional cladding mass they represent will significantly increase the base shear and overturning demand in seismic zones. This paper investigates the use of a light structural system comprised of a steel stud wall assembly partially embedded in a thin layer of concrete to obtain composite action. Fiber reinforced polymer (FRP) composites are also included to increase the blast resistance and aid in keeping the panel weight to a minimum. Two full-scale composite steel stud walls are designed, constructed, and tested dynamically in the BakerRisk shock tube. The stud walls consist of back-to-back 150 mm deep, 14 gauge (1.8 mm thick), cold-formed steel studs spaced at 610 mm on center. Both specimens have a 50 mm thick normal weight concrete layer, reinforced with welded wire mesh that is welded to the stud compression flanges to achieve composite action. Two layers of Tyfo® SEH-51A fiber reinforced composites are used on the tension flange of the steel studs. A single layer of Tyfo® SEH-51A composites is used on the tension face of the concrete layer between the studs for one of the specimens. Web stiffeners are used at the bearing support to prevent premature web crippling shear failure of the specimens. The stud walls are analyzed using single-degree-of-freedom (SDOF) models. A non-linear moment-curvature relationship, accounting for actual material constitutive properties, is used for determining the resistance function of the walls. Blast pressure and impulse data from the shock tube tests is used to compare analytical predictions to the measured displacement-time response. Analytical predictions of panel response for both tests are within ten percent of the observed response based on displacement.

Blast Response of Lightly Attached Concrete Masonry Unit Walls

Exterior wall panels of structures are often constructed of concrete masonry units (CMUs), commonly known as concrete blocks. These walls may become a debris hazard to building occupants when high explosives, for example, a terrorist vehicle bomb, are detonated outside of a building. A recently completed series of physical experiments is being used to develop methods for predicting the hazard levels associated with CMU walls. Retrofitting techniques have been developed to mitigate these hazards. The experiments included nonretrofitted CMU walls as well as several different types of retrofits. Test data, high-speed video, and posttest inspection of the experiments were used to assess the parameters that affect the response of CMU walls and retrofit systems. The objective of the research presented in this paper is to collect data on the blast response of CMU walls so that improvements can be made to the previously developed Wall Analysis Code (WAC).

The SMART system: an integrated application of automation and information technology in production process

The future survival of Japanese construction industry may depend on the applications of automation technology and information technology. Many of the efforts undertaken in this directions are carried forth in the context of Computer Integrated Construction (CIC). Several automated construction systems and integrated information management systems have been developed as prototypes of CIC implementation. In this paper, a prototype construction system is described, that is SMART System (Shimizu Manufacturing system by Advanced Robotics Technology). The SMART system is an integrated automated construction system which automates a wide range of construction procedures, including erection and welding of steel-frames, laying of concrete floor planks, installation of exterior and interior wall panels, and installation of various other units. It also utilizes information technology extensively in the form of integrated information management system which integrates a wide range of design, planning and management activities of the project. The SMART system was introduced in an office building project in Nagoya, Japan. The project was successfully completed in February, 1994.

Soil-Related Damage to Tilt-Up Structures

A common form of construction in the United States is tilt-up construction, where the exterior concrete walls are cast in segments upon the floor slab and then tilted up into position. The purpose of this paper is to describe typical damage to tilt-up buildings due to soil movement. Expansive soil can damage the interior concrete floor slab due to center lift. A second type of soil movement that can damage tilt-up structures is slope movement. Slope movement can pull apart adjacent panels and open up the joints in the interior floor slab. A third type of soil movement that can damage tilt-up structures is settlement. In this case, settlement of the exterior wall panels results in diagonal cracks that frequently develop at windows or door corners. Design methods to improve the performance of tilt-up buildings include removing or treating the expansive soil below the floor slab, providing stronger ties at the joints between wall panels and segments of the floor slab, as well as installing piles or piers to support the perimeter footings and transfer the tilt-up wall panel loads to competent bearing strata.

Design-Construction of United Bank Tower

Bruce R. Wolfe, P.E. Project Manager Structural Consultants Inc. Denver, Colorado Presents the design-construction highlights of a $13 million high rise office building in Colorado Springs. A major feature of this prestigious building is the integration of both architectural and structural precast, prestressed concrete components andespecially the dual function of exterior wall panels which provide aesthetic expression and serve as loadbearing elements.

DESIGN OF FRAME

This fifth paper in the series of articles on Design Considerations for a Precast Prestressed Apartment Building treats the design of the frame. The structural frame for this 24story apartment building consists of double tees, beams, and columns at the interior of the building and load bearing wall panels at the exterior of the building. Since the exterior wallpanels are considerably stiffer than the columns, lateral loads will not be considered in the design of the beams and columns. The beams are dapped to receive the double tees, and beam-to-column connections are internal so that the ,depth of the structure is minimized. The first part of the paper covers -the detailed design calculations of the girders, columns, transfer girder, and columns supporting the transfer girder. The second part of the paper presents a commentary on the frame design calculations. Explanations are given regarding the design of the floor girders, the framing at service core, the columns, and the transfer girder. Typical reinforcement diagrams, end condition details, beam-to-column connection, column-to-column connection, and column base details are given. An Appendix at the end of the paper presents the calculations for estimating the prestress losses. For the readers' convenience the meaning of each mathematical symbol used in the text is summarized in alphabetical order at the end of the paper.