Roof Panels Research Articles

Influence of Edge Restraint on Clip Fastener Loads of Standing Seam Metal Roof Panels

Abstract This study investigates the effect of boundary conditions on the structural load paths within standing seam metal roof (SSMR) panel specimens subjected to uplift wind pressures. The objective is to determine the effect of boundary conditions (restrained or free) on observed load distributions among clip fasteners installed within a SSMR test specimen. Two roof specimens with instrumented clip fasteners were installed in a steel pressure chamber and subjected to static uplift pressures, while measuring panel deflection and clip fastener load distributions. The test specimen boundary conditions were modified in turn to represent field panel location (all free boundaries), gable panel (one restrained boundary, long dimension), eave panel (one restrained boundary, short dimension), and a corner panel (having two adjacent restrained boundaries). The load-displacement characteristics of the SSMR system were determined in a third specimen. The study found statistically significant differences in clip fastener loads, among the first three fastener rows away from the crosswise panel restraint, i.e., eave boundary condition. The gable boundary appeared to have less influence on load on the nearest fasteners. For the eave boundary condition, the measured load on the three exterior fasteners was about 40 % lower than the total fastener load on interior clips located just 3 m (10 ft) away. The results suggest why clip failures seldom occur in corner locations during uplift pressure tests. An empirical design method is proposed for predicting loads on clip fasteners installed near roof boundaries. More importantly, the design of SSMR roofing can be made more efficient, since it is shown that eave clip fasteners carry less than half the load of the interior fasteners, if other failure mechanisms (i.e., sheet tearing or boundary anchor failure) do not control the roof edge failures of installed SSMR.

Energy efficient surfaces on building sandwich panels—A dynamic simulation model

The choice of building envelope is critical for the energy performance of buildings. The major part of the energy used by a building during its lifetime is used for maintaining a suitable interior thermal climate under varying exterior conditions. Although exterior heat radiation properties (i.e. total solar reflectivity and long wave thermal emissivity) have been well accepted to have a large impact on the need for active cooling in warmer climate, the effect of a reduced thermal emissivity on interior surfaces on the building thermal energy flux is rarely studied. This paper addresses the sensitivity of the thermal energy flux through a sandwich panel, by systematically varying the surface thermal emissivity (both interior and exterior) and total solar reflectance of exterior surface, for three geographical locations: southern, middle and northern Europe. A model is introduced for calculating the effect of both interior and exterior optical properties of a horizontal roof panel in terms of net energy flux per unit area. The results indicate potential energy saving by the smart choice of optical properties of interior and exterior surfaces.

Deterministic-statistical analysis of a structural–acoustic system

The purpose of this paper is to develop an efficient approach for vibro-acoustic analysis. Being simple and representative, an exited plate–acoustic system is selected as a validation case for the vibro-acoustic analysis as the system presents one two-dimensional statistical component (modal dense structure panel—plate) connected to the other component (deterministic acoustic volume—cavity) through the area junction over a surface domain, rather than at a line boundary. Potential industrial applications of the system vibro-acoustic analysis would be in acoustic modelling of vehicle body panels such as the cabin roof panel, and door panels for the boom noise analysis. A new deterministic-statistical analysis approach is proposed from a combination or hybrid of deterministic analysis and statistical energy analysis (SEA) approaches. General theory of the new deterministic-statistical analysis approach is introduced. The main advantage of the new deterministic-statistical analysis approach is its possibility in place of the time consuming Monte Carlo simulation. In order to illustrate and validate the new deterministic-statistical analysis approach, three approaches of the deterministic analysis, the statistical energy analysis and the new deterministic-statistical analysis are then applied to conduct the plate–acoustic system modelling, and their results will be compared. The vibro-acoustic energy coupling characteristic of the plate–acoustic system will be studied. The most suitable frequency range for the new approach will be identified in consideration of computational accuracy, information and speed.

Bending Performance of Composite Wood I-Joist/Oriented Strand Board Panel Assemblies

This study examined the bending performance of composite I-joist/oriented strand board (OSB) structural roof panels. The 1.22-m-wide panels were fabricated from commercially available I-joists with OSB sheathing bonded to the top and bottom I-joist flanges. To provide baseline bending performance, two sets of 10 bare I-joists were tested to failure in four-point quasistatic bending. The first consisted of 4.72-m-span, 241-mm-deep joists, and the second set consisted of 7.16-m-span, 356-mm-deep joists. Two sets of 10 I-joist/OSB panels fabricated with identical I-joists of the same spans were tested in four-point bending. Results of the bend tests showed strength gains of 59 to 124 percent and stiffness gains of 79 to 115 percent on a per-joist basis for the I-joist/OSB panels. While the bare I-joists primarily exhibited bending failures, the panels predominantly failed in shear. These strength and stiffness gains and the shift in failure mode indicate that the bonded OSB sheathing significantly improved panel bending strength. A transformed section analysis predicted panel stiffness reasonably well and indicated that shear failure was the most likely panel failure mode. Finally, four specimens were tested under sustained loading equal to 55 percent of the 5 percent parametric lower tolerance limit. Two of the specimens tested under sustained loading failed in creep rupture. Results of this study indicate that the roof panels show promise for practical application as long-span, pre-insulated structural members. However, creep deformation and creep rupture need further study, as does the durability of the I-joist–OSB bond line.

Development of Liftgate Hinge-to-Roof Sealing Gasket Material for Uncoated Steel Roof Panels

Development of Liftgate Hinge-to-Roof Sealing Gasket Material for Uncoated Steel Roof Panels

P02-150 - Psychiatric intensive care units - designed for the patient ….designed for the environment

AimsThis poster explores how Psychiatric Intensive Care Units can be designed using “green” technology in order to be environment-friendly whilst also meeting patient needs.MethodAnalysis of the new PICU at Hellesdon Hospital, Norfolk and Waveney Mental Health NHS Foundation Trust, United Kingdom. We describe how the architecture has been adapted from the standard mental health unit model to facilitate more intensive supervision. We will also examine the building design features that have been incorporated to ensure the lowest possible carbon footprint.ResultsRollesby Ward (PICU) at Hellesdon Hospital won the Broadland design award 2009. It is a new, purpose built, building that provides a safe, user-friendly unit with en-suite accommodation; and rooms for seclusion, therapeutic activities and one to one sessions. The use of key cards and the layout of the bedrooms and lounge areas maintain patient privacy and dignity. A number of technologies have been used to minimise the building's carbon footprint. These include maximising usage of natural light and ventilation, underground rainwater tanks for flushing toilets, photovoltaic roof panels, and ground source heat pumps. Since the PICU has opened, 62.63 mwh of energy (35.57 tons of carbon) has been saved.ConclusionNew build psychiatric units can successfully incorporate design features that deliver a better patient and therapeutic environment whilst also minimising the consumption of energy and the size of the carbon footprint.

Dynamic Performance Analysis of a Light Van Body-In-White Structure

Requirement for low emissions and better vehicle performance has led to the demand for lightweight vehicle structures. Lighter gauge panels are being used to construct the body-in-white (BIW) monocoque structure, which is the basic component of the vehicle body. Since lighter gauge panels tend to generate more vibration and interior noise, it is necessary to optimize the dynamic performance of lightweight vehicle structures in order to achieve acceptable levels of vibro-acoustic performance. The design of a light commercial van structure has evolved over the years and through a lightweighting exercise the current BIW is about 10 per cent lighter than the previous BIW even though the volume capacity was increased by 15 per cent and the load-carrying capacity by 18 per cent. In this study, the dynamic performance of the current production light van BIW structure is investigated. Its performance is assessed against the structural dynamic performance standards which have been established for this class of structures. While the input mobility performance was found to exceed the standards easily, the modal mobility performance was found to be unsatisfactory owing to the occurrence of local panel resonant modes in the two side panels. A finite element model of the structure was developed to study the effect of adding stringers to the roof and side panels to eliminate some of the local panel modes and thus to improve the dynamic performance of the structure.

Heating and Cooling Performance of Building Integrated Solar Roof Panels

With the high proportion of building energy consumption in the total energy consumption, it is of great importance to relieve the shortage of conventional energy resources and improve the building environment by incorporating solar energy into buildings. A new type solar roof panels were designed and tested in the present paper, which perfectly achieves the integration of solar equipment with building envelope. This panel can act as the construction component for building envelope and completely removes the double-skin mode for conventional solar equipment, as well as the functional equipment for heating and cooling collecting. Corrugated colored steel roof panel was tested under various climate conditions and operation conditions. The results show that in a typical sunny day the average heat collecting efficiency is 49% and the average cooling capacity is 100W/m2. In a cloudy day, the average heat collecting efficiency is 41% and the average cooling capacity is 84W/m2.

A study on mechanical characteristics of the friction stir welded A6005-T5 extrusion

In this paper, A6005-T5 extruded aluminum alloy sheets which are used for floor, roof or wall panels of railroad vehicles were welded by the friction stir welding (FSW) and gas metal arc welding (GMAW) techniques. The mechanical characteristics including the tensile strength, micro-hardness and fatigue strength of the FSW joint were compared to those of the base metal and GMAW joints. In order to determine the relationship between the welding variables of FSW and the mechanical characteristics of the joint, the response function was derived using the least square method and the sensitivity analysis was performed. The rotational speed, welding speed and tilting angle of the welding tool were chosen as design variables. On the basis of the Plackett-Burman design table, eight different FSW experiments were done, and then the effects of design variables on the mechanical characteristics of the FSW joint were analyzed. The result showed that the welding speed has a most significant effect on the tensile and fatigue strength. In the case of the micro-hardness, the effect of the tilting angle was the biggest.

Experiment and Finite Element Study on the Structural Behavior of Steel Sandwich Panels

This work try to deal with the analysis of a class of sandwich panels widely employed in engineering constructions. In order to study its structure behavior, a systematic experimental study on both roof and wall sandwich panels filled with Polyurethane foam (PU) under uniformly distributed load is conducted. Informed by the tests, appropriate finite element models are developed to model the tests.

Wind-Uplift Capacity of Residential Wood Roof-Sheathing Panels Retrofitted with Insulating Foam Adhesive

This research evaluated and compared the wind-uplift capacity of wood roof-sheathing panels fabricated by using nails with retrofitted roof panels made with nails and closed-cell sprayed polyurethane foam (ccSPF) adhesive. In hurricane-prone areas, structural retrofits of light-framed wood roof structures are needed to mitigate wind damage to existing residential roof structures because the majority of these have inadequate design strength to resist hurricane-force winds. A steel pressure chamber connected to a pressure loading actuator was used to conduct uplift pressure tests on 186 roof panels. The panels were fabricated using 11.1 mm (7/16 in.) thick oriented strand board sheathing fastened to nominal 51 by 102 mm (2 by 4 in.) southern yellow pine framing members spaced 610 mm (24 in.) apart. There were 123 panels tested in typical as-built conditions, and 63 panels tested after they were retrofitted with ccSPF. The parametric study determined the effect of several factors on wind-uplift failure pressure: (1) three nail types, (2) two nail spacings, and (3) three retrofit methods using ccSPF. The hypothesis tested was that ccSPF (traditionally used as wall and roof insulation in houses) could also act as a structural adhesive to increase the wind resistance of existing roofs. Standardized tests do not currently exist for wood roof panels, and so a uniform, static pressure-test protocol was developed on the basis of the ASTM E330, Method B Test Procedure. The results showed that ccSPF retrofits increase the wind-uplift capacity of the pre-1994 code-minimum wood roof panels by as much as 250–300%. This finding is important because it could provide a means to improve the wind resistance of these older roof designs, which may still account for more than 60% of the existing residential inventory. The distributions of roof-failure capacities of as-built and retrofitted roof panels are presented, and statistical parameters are presented for use in developing performance-based design criteria. The documentation and approach is presented as a model test protocol as the basis of a standardized wind-uplift test method for wood roof-sheathing panels.

Simulation Tests to Assess Occupational Exposure to Airborne Asbestos from Artificially Weathered Asphalt-Based Roofing Products

Historically, asbestos-containing roof cements and coatings were widely used for patching and repairing leaks. Although fiber releases from these materials when newly applied have been studied, there are virtually no useful data on airborne asbestos fiber concentrations associated with the repair or removal of weathered roof coatings and cements, as most studies involve complete tear-out of old roofs, rather than only limited removal of the roof coating or cement during a repair job. This study was undertaken to estimate potential chrysotile asbestos fiber exposures specific to these types of roofing products following artificially enhanced weathering. Roof panels coated with plastic roof cement and fibered roof coating were subjected to intense solar radiation and daily simulated precipitation events for 1 year and then scraped to remove the weathered materials to assess chrysotile fiber release and potential worker exposures. Analysis of measured fiber concentrations for hand scraping of the weathered products showed 8-h time-weighted average concentrations that were well below the current Occupational Safety and Health Administration permissible exposure limit for asbestos. There was, however, visibly more dust and a few more fibers collected during the hand scraping of weathered products compared to the cured products previously tested. There was a notable difference between fibers released from weathered and cured roofing products. In weathered samples, a large fraction of chrysotile fibers contained low concentrations of or essentially no magnesium and did not meet the spectral, mineralogical, or morphological definitions of chrysotile asbestos. The extent of magnesium leaching from chrysotile fibers is of interest because several researchers have reported that magnesium-depleted chrysotile fibers are less toxic and produce fewer mesothelial tumors in animal studies than normal chrysotile fibers.

Reliability analysis of roof sheathing panels exposed to a hurricane wind

Light-frame wood roofs are frequently used in the US for residential and commercial construction. High wind events, such as hurricanes, may cause severe damage to these structures by breaking the roof envelope and allowing penetration of wind-driven rain. Most previous wood panel reliability studies have used static, uniform wind pressure load models and code-specified load distribution rules for analysis. This study re-estimates the reliability of roof sheathing panels exposed to a specific hurricane event using actual wind pressure data and a more refined structural analysis model. The objective is to examine the adequacy of the simplified wind load and structural analysis models used for roof panel reliability analysis. In the procedure here, panel failure behavior is modeled by individual fastener extraction from the panel as dynamic wind pressure is increased. For reliability analysis, the limit state is based on panel pull-off. The results show that the use of a refined model provides some significant differences in panel reliability found from simplified techniques.

P.2.b.024 Lithium preferentially increases neurogenesis in the ventral but not dorsal hippocampus of stressed BALB/c mice

This paper concerns energy performance of ETFE (ethylene tetrafluoroethylene) cushion roof integrated photovoltaic/thermal system (CIPV/T system). An experimental set-up composed of a three-layer ETFE cushion roof and amorphous silicon photovoltaic panels (a-Si PV) has been developed to investigate system energy performance. A series of tests from 10:00 a.m. to 5:00 p.m. were successfully carried out within ambient temperature of around 9 °C and 39 °C in December 2014 and August 2015, respectively. On the whole, experimental results show that this system operated smoothly and steadily. In this study, typical weather conditions ranging from low solar irradiance in winter to strong solar irradiance in summer were selected to investigate system energy performance, including solar energy utilization and structural parameters of ETFE cushion roof.Solar energy utilization could be evaluated by electricity and temperature which represent photovoltaic and thermal performance, respectively. It is found that average total and net electricity were 54.5 W h and 42.9 W h, indicating that this integration ensures the CIPVT system to be independent on external electricity. Meanwhile, measured air temperature inside ETFE cushion roof was 31.2–67.8 °C and it was 16.8–31.0 °C higher than ambient air temperature, showing an attractive potential in collecting thermal energy. Moreover, virtual system efficiency in terms of electricity and thermal energy was 25.5% based on average experimental results and an approximate method. This reasonable system efficiency is due to annealing effects of a-Si PV under high temperature conditions. For temperature distribution of ETFE cushion roof, temperatures on top-layer and bottom-layer ETFE foils were significantly lower than that on middle-layer ETFE foil, resulting in less temperature effects on structural behavior of ETFE cushion roof. This study could provide useful observations and explanations for evaluating energy performance of the CIPVT system concerning solar energy utilization.

OPTIMIZATION MIX PROPORTION OF EXPANDED POLYSTYRENE LIGHTWEIGHT CONCRETE FOR MANUFACTURE W ALL AND FLOOR PANELS OF BUILDING ASSEMBLED

The use of prefabricated lightweight concrete panels like wall, floor, roof can help cut down construction cost while maintains the quality of the building. This method has been used effectively in many developed countries and has proved to be appropriate in Vietnam condition. This paper deals with fabrication expanded polystyrene (EPS) lightweight concrete panels base on increasing strength of mortar matrix and optimization porous structure. In this research, we studied EPS lightweight concrete with density of 875 - 1150 kg/m3 and compression strength of 7.5 - 15 MPa for manufacturing wall panels. EPS lightweight concrete with density of 1275 kg/m3 and compression strength of 20 MPa for manufacturing floor and roof panels.

Transparent Cubical Glass Building in Madrid

An ultimately transparent glass building in almost cubical form of 30x30x21 m, to function as the future entrance building of the Santander Bancopolis complex southwest of Madrid. Conceptual design by architect Alfonso Millanes and structural design by Octatube. The structure is composed of ultra slender cable stayed tubular columns and trusses placed in a grid of 5m and cladded with insulated glass made from fully tempered outer panels and heat strengthened laminated inner panels. Size of all glass panels is 2.5 x 2.5 m². The insulated glass ensures additional stabilisation of the overall enveloping structure. The roof panels are partly twisted to obtain a fluent slope for drainage. The roof gutters are positioned at 2.5 m from the roof edge, thus creating a free glass edge. The side walls of the gutters are made of insulated glass panels. The glass type chosen is ‘extra-white’, emphasizing the glass cube as a sparkling crystal in the landscape.

Electromagnetic analysis of an AC electric arc furnace including the modeling of an AC arc

PurposeThe purpose of this paper is to present a 3D finite element model of the electromagnetic fields in an AC three‐phase electric arc furnace (EAF). The model includes the electrodes, arcs, and molten bath.Design/methodology/approachThe electromagnetic field in terms of time in AC arc is also modeled, utilizing a 3D finite element method (3D FEM). The arc is supposed to be an electro‐thermal unit with electrical power as input and thermal power as output. The average Joule power, calculated during the transient electromagnetic analysis of the AC arc furnace, can be used as a thermal source for the thermal analysis of the inner part of furnace. Then, by attention to different mechanisms of heat transfer in the furnace (convection and radiation from arc to bath, radiation from arc to the inner part of furnace and radiation from the bath to the sidewall and roof panel of the furnace), the temperature distribution in different parts of the furnace is calculated. The thermal model consists of the roof and sidewall panels, electrodes, bath, refractory, and arc. The thermal problem is solved in the steady state for the furnace without slag and with different depths of slag.FindingsCurrent density, voltage and magnetic field intensity in the arcs, molten bath and electrodes are predicted as a result of applying the three‐phase AC voltages to the EAF. The temperature distribution in different parts of the furnace is also evaluated as a result of the electromagnetic field analysis.Research limitations/implicationsThis paper considers an ideal condition for the AC arc. Non‐linearity of the arc during the melting, which leads to power quality disturbances, is not considered. In most prior researches on the electrical arc furnace, a non‐linear circuit model is usually used for calculation of power quality phenomena distributions. In this paper, the FEM is used instead of non‐linear circuits, and calculated voltage and current densities in the linear arc model. The FEM results directly depend on the physical properties considered for the arc.Originality/valueSteady‐state arc shapes, based on the Bowman model, are used to calculate and evaluate the geometry of the arc in a real and practical three‐phase AC arc furnace. A new approach to modeling AC arcs is developed, assuming that the instantaneous geometry of the AC arc at any time is constant and is similar to the geometry of a DC arc with the root mean square value of the current waveform of the AC arc. A time‐stepping 3D FEM is utilized to calculate the electromagnetic field in the AC arc as a function of time.

Paper Tube Application (A Paper Tube Shelter)

Abstract Emergency events caused by natural disasters can cause people to be homeless as their homes destroyed due to such events. Architects and structural researchers proposed several aspects (concepts) to adapt the matter case. One of such concepts is the paper tube which in the last decade considered being a new trend. The paper discuss the application of the paper tube structure that was first been innovated by Shegaru Ban. The paper analyzes a temporary structure in a form of modular panels that was made of wooden frames filled with paper tubes. Paper tubes are to be arranged linearly taking the length of the panel (parallel to the long direction of the panel frame side). The aim of this research is to examine a shelter that was been built as an emergency shelter with the use of paper tubes. The paper examines the shelter individual parts (wall panels, roof panels, floor panels, and foundation panels). The research begins with how the criteria being specified, and the reasons that govern the selection of such system of construction. The paper tube shelter and system due to serve in both fields of application the civilian and the militaries.

Thermal Performance of Green Roof Panels in Sub-Zero Temperatures

Abstract To date, much of the research on green roof technology has focused on the capacity for these systems to contribute to the cooling of buildings during summer months. The thermal performance of green roofs in cold climate conditions is critical to understanding the potential of these roofs to decrease energy use in buildings during winter. This paper compares the behavior of two green roof systems with that of a conventional built-up roof by making use of a novel hot box testing apparatus. The green roofs tested are classified as extensive systems. Each system included: a 3 mm thick styrene butadiene rubber waterproofing membrane, 0.2 mm thick polyethylene slip sheet, a 76 mm thick extruded polystyrene insulation layer, 2 mm thick filter fabric, a 51 mm drainage layer followed by a 2 mm thick filter cloth, either 100 mm or 150 mm growing medium, and a 25 mm thick wild flower vegetated mat. The conventional roof consisted of a 2 mm thick layer of Kraft™ vapour retarder bonded with insulation adhesiv...

Test method for roof panels to be used for passive fire roof venting

The current New Zealand prescriptive code for fire safety allows unlimited firecell floor area if at least 15% of the roof area is designed for “effective fire venting”. However neither a definition nor performance criteria for “effective fire venting” is provided. Transparent and semi-transparent ‘plastic’-type panels that have been installed for natural lighting requirements have been assumed to provide passive fire venting, based on misperceptions of generic ‘plastic’ performance in the event of a fire. The fire venting performance of these roof panels has not been proven. Therefore guidance on the use of roof panels for passive fire venting is required.