Arched Roof Research Articles

Increased Life for Open-Hearth Furnace Roof Lining

Reasons are studied for the short life of sprung-suspended roofs of open-hearth furnaces and refractory objects are developed with reduced thermal conductivity and a special hook. During refractory laying a shrinkage-free high-temperature laying mortar is used. OAO Nizhnyi Tagil’ Metallurgical Combine organizes industrial output of the refractories developed. Industrial testing is carried out in open-hearth furnace arched roofs of OAO Nizhnyi Tagil’ Metallurgical Combine (NTMK) and ZAO Nizhnyi Sergi Metalware and Metallurgical Plant (NMMZ). According to test results the increase in roof life is 20 – 30%, and the economic effect for two open-hearth furnaces is 4,656 million rubles per year.

The Effect of the Numerical Wind Tunnel Simulation Results of Arched Roof for Different Turbulence Models

Using the FLUENT software, this paper taking the wind load shape coefficient in the current code for the design of building structures as the comparison standard, have numerical wind tunnel simulation of the wind the surface wind pressure on arch roof. It focused on the effect of the different turbulence models on the numerical simulation, such as Spalart-Allmaras, Standard k ε, RNGk ε, Realizablek ε, Standard k ω, SST k ωand RSM. It provided reasonable reference for selection of turbulence model.

Monitoring and Results Analysis of Tunnel Engineering

Through to the Henan tunnel engineering and observation hole, peripheral displacement measurement, measurement of subsidence of arch roof and surface subsidence measurement on-site real-time dynamic testing, obtained their changes over time curve, and the tunnel monitoring results were analyzed, thus improving the tunnel design and correctly guide the construction, ensure the safety and economy of the tunnel engineering.

Assessment of ASCE 7-10 Standard Methods for Determining Wind Loads

The purpose of this paper is to discuss issues associated with ASCE 7-10 standard methods for determining wind loads on buildings and other structures that warrant comment, correction, or improvement. The assessment is intended to serve as a resource in the development of a new version of the ASCE 7 standard and to stimulate a wider participation in that development by the structural engineering community. Issues discussed in the paper include: wind speeds in nonhurricane regions; alternative analytical methods for determining wind loads and wind effects on main wind force resisting systems and components and/or cladding; aerodynamic pressure coefficients; pressures on rooftop equipment; component and cladding pressures on arched roofs; and the wind tunnel procedure. It is noted that the ASCE 49 standard essentially covers wind tunnel testing, rather than the wind tunnel procedure, of which wind tunnel testing is only a part.

Comparing of Temperature Variation with Different Types Greenhouse

Greenhouse temperature of the three different types was measured under sunny winter weather conditions. The variation regularity of greenhouses temperature with outdoor temperature was studied according to the monitoring data of experimental greenhouse, which was different roof and floor structure. The results showed that the greenhouse temperature of the herringbone roof construction higher than the greenhouse of the serration roof construction; the greenhouse temperature of the serration roof construction is higher than the greenhouse of arch roof construction. Through analysis of temperature variation on the different type greenhouse, it will provide theoretical basis to construct greenhouse in different areas.

Effects of a UV-absorbing greenhouse covering film on tomato yield and quality

The effect of blocking the ultraviolet (UV) solar radiation using a UV-absorbing low density polyethylene (PE) film on tomato crop yield and fruit quality was evaluated in a two-year study in two arched roof greenhouses located in Central Greece. The UV-A and UV-B radiation transmission values of the greenhouse covered by the UV-absorbing PE film during the first year were 0.4% and 1.2%, respectively and increased to 0.8% and 1.3% in the 2nd year, while the respective values in the greenhouse covered by a traditional PE film were 20.7% and 12.5% during the 1st year and 28.7% and 26.7% during the 2nd year. Under the UV-absorbing film the number of insect injured fruit was reduced and the marketable yield was similar or higher than that under the common PE film, while fruit quality characteristics (size, shape), nutritional value (ascorbic acid and lycopene) and organoleptic quality (pH, titratable acidity and total soluble solids) were similar under both covering materials. Moreover, the reduction of incoming UV radiation had an appreciable effect on fruit skin color, indicating an effect on pigments other than lycopene.

The Selection of Pressure Velocity Coupling Algorithm in the Numerical Wind Tunnel of Arch Roof

using the FLUENT software, this paper taking the current code for the design of building structures as the comparison standard, have numerical wind tunnel simulation of the wind the surface wind pressure on arch roof. It focuses on the analysis of the effects of three kinds of pressure velocity coupling algorithm on the numerical simulation results, respectively SIMPLE, SIMPLEC, PISO, to provide a basis for the reasonable selection of algorithm.

SURVEY PROBLEMS AND REPRESENTATION OF ARCHITECTURAL PAINTED SURFACES

Abstract. The painted surfaces of a building are generally vertical walls and flat roofs or arched roofs. The detection of these objects must be prepared according to the reason why the metric operation is designed; metric control of the whole performance practice is crucial for the result to matches the predetermined needs. It's now clear that the acquisition of metric data, as the whole process of detection, can certainly not be left to an unidentified automation. The mere representation of point clouds transformed in mesh and processed into 'maps' can cover only a few limited requirements. Conservation and restoration also require the transformation of "discrete" three-dimensional data into two-dimensional representations, resulting in geometric transformations that require a new mindset, especially considering hardware and software potential. We want to propose a new type of projection end analysis as base for the development of representation systems that will transform three-dimensional models in two-dimensional projections for the conservation and restoration.

Analysis and Design of Concrete Cylindrical Shell Roof Structure

Combined with the roof of a warehouse the arched shell roof structure is select, simulation Numerical simulation is carried out for the arched shell roof structure system by the ANSYS finite element method, the deformation and stress are obtained which meet the specification requirements. So it is reasonable to select the thin vaulted roof. Finally, the arrangements of the two prestressing tendons of prestressed concrete beams in the framework and the matter which needs to be paid attention to during designing are given, and these can provide reference for similar finite element solution and design of the structural system.

Large Building Overhead Installation Control Surveying

In the process of urbanization, along with a high degree of integration of the intensification of land use and urban architecture function, many large-scale large buildings have appeared which have enormous architectural space and the structure is complex. They are the city's landmarks and are the import integration of urban functions and landscape. During the construction of complex steel structure the high altitude installation need high demand to control surveying. It requires not only the surveying accuracy, precision, but also high surveying techniques on the spatial structure of three-dimensional positioning, docking, and assembly. Conventional planar and high level processing surveying mode cannot meet the construction needs. In this paper the arched surface steel roof truss high altitude installation project of China Tianjin West Railway Station is researched which has north-south length of 394 meters and east to west span 126 meters. The research aims to establish an accuracy of high three-dimensional surveying control network. This paper presents a specific implementation method of control surveying. And though data processing, accuracy evaluation and the analysis of engineering applications results, we verify the correctness of the method. This method support spatial location and geometric characteristics for arched surface of steel roof truss high attitude installation. It ensures the project successfully implemented.

EFFECT OF TWO NEW COVER MATERIALS ON GREENHOUSE ENERGY CONSUMPTION AND COOLING LOAD

The aim of this work was to study the effects of a new polyethylene (PE) film with high reflectance and absorption in near infrared radiation (NIR-PE film) and of a PE film with low transmittance in infrared radiation IR (IR-PE film), on the greenhouse microclimate, energy consumption and on growth and yield of a hydroponic tomato crop. Compared to a common PE film (C-PE), the IR-PE film, had 75% lower transmittance in IR, while the NIR-PE had 78% lower transmittance in IR and 42% higher reflectance in NIR. Films were evaluated experimentally in three similar arched roof greenhouses, two covered with the new covering materials and the third one by a C-PE film. The greenhouse and outside microclimate parameters along with crop growth and production were recorded. During the winter period, no significant differences of air temperature and relative air humidity between the tested greenhouses were found. The air vapour pressure deficit (VPD) values observed were relatively low (i.e below 0.5 kPa) during the night period, leading to condensation over the cover. The total energy consumption was 10% lower in the IR-PE covered greenhouse than in the C-PE covered greenhouse. During the summer period, the air temperature in the greenhouse covered by the NIR-PE was 2°C lower than the air temperature of the C-PE covered greenhouse.

IMPROVEMENT OF GREENHOUSE MICROCLIMATE DISTRIBUTION BY MEANS OF AIR MIXING FANS

The objective of this work was to experimentally investigate the influence of air mixing fans on air temperature and humidity distribution in an arched roof greenhouse. The greenhouse was occupied by a tomato crop and equipped with two side roll-up openings for ventilation, a PVC pipe heating system and a fan coil heater. Furthermore, for air mixing purposes, an air mixing fan was used. Air temperature and relative humidity was simultaneously recorded in 17 positions equally distributed inside the greenhouse. Concerning the effects of air mixing fan on microclimate distribution, it was found that the mixing fan increased microclimate homogeneity. On the other hand, the use of fan-coil heater was found to increase microclimate heterogeneity. The maximum absolute air temperature and relative humidity difference (observed above the crop) between the centre of the greenhouse and the different measuring positions at the same level, was about 1°C and 4% respectively when the air mixing fan was not used and about 0.4°C and 1% respectively, when the air mixing fan was used. The use of a fan-coil heater increased the above mentioned differences to the level of about 1.7°C and 6% respectively when the air mixing fan was not used and about 1°C and 3% respectively, when the air mixing fan was used. Finally, it was observed that the use of an air mixing fan and/or a fan-coil heater reduced the greenhouse air relative humidity.

A Study on the Selection of Optimal Roof Type for Low-rise buildings group – in a View of Wind Pressures Action

A series of aerodynamic experiments were conducted to measure the surface pressures on tandem arranged low-rise buildings models with variant roof types in the wind tunnel. An electro-scan valves system was used to get the simultaneous pressures distribution on the models. With these conditions, the characteristics of surface pressures were detail calculated and compared. The results shown, the mean wind pressures on the low rise-to-span ratio models will lower then the higher ratio ones. But the fluctuating and peak pressures on the roof, especially at the corners, will be increased. About the shielding effect, it will reduce the surface pressures and the structural loadings. But in the cases of small gap between buildings, the peak pressure will be increased at side wall and roof corners of buildings. Over all, for the different types of roofs, the shielding effects on gable roof models are most evident and the arch roof models are less. For the dome-like roof models, the shielding effects are trifling. The designer may take consideration above these characteristics and benefited to optimize their structure design of the roofs.

A Study on the Equivalent Static Wind Loadings on the Arched Roof Frames of Low-Rise Buildings in Atmospheric Boundary Layers

A series of wind tunnel aerodynamic experiments were conducted to investigate the wind loads on the low-rise buildings with arched roofs. The wind loadings were calculated from the simultaneous measured wind pressures data over all of the models surfaces in a simulated open terrain exposure atmospheric boundary layer. With these data the equivalent static wind loads (ESWL) of fluctuating wind pressures acting on buildings frames were evaluated and the results of equivalent static wind loads were compared with the 2006 version design codes of wind loadings on buildings in Taiwan. The design codes suggested the direction of wind acting on the low-rise buildings roofs were normal to the ridges of roofs. In this study results shown, the equivalent static wind loads caused by the approaching turbulent flow may exceed the suggested values by codes. So the peak response of structural frames should be considered carefully.

Mechanical properties of roller bent wide flange sections — Part 1: Experimental investigation

Arched roofs are built more and more with roller bent wide flange sections, serving as structural elements. Roller bent wide flange sections are manufactured from straight hot-rolled wide flange sections by a process called roller bending. The material is cold worked during forming, inducing a new distribution of mechanical properties across the section which is different compared to its original state. For the design of arches the use of original or nominal strength properties of the straight material neglects the influence of the roller bending process. This may lead to conservative or nonconservative designs. This paper presents the results of an extensive experimental investigation of the mechanical properties of roller bent wide flange sections. It comprises tensile tests and compression tests on coupons taken from roller bent sections and their straight counterparts. The results show that the roller bending process alters the mechanical properties of the material non-uniformly over the cross-section. In this paper the experimental results are presented. In a companion paper the experimental results are used to arrive at a set of equations that yields different stress–strain curves for specific zones across the roller bent steel section.

Paddington station: span 4 refurbishment and strengthening

London's Paddington station, the terminus of the Great Western Railway, was the masterpiece of the company's first chief engineer, Isambard Kingdom Brunel. The core of the station is a magnificent three-span arch roof on slender iron columns. However, in the early part of the twentieth century, the station was much extended, most notably by the addition of a grand fourth span to the roof structure. In recent times, span 4 has been neglected and is now undergoing refurbishment to restore it to its proper place as a grade 1 listed structure, alongside the remainder of the station buildings. The project will complete the renovation of the station's entire roof and complement the improved passenger information systems and retail developments. This paper first reprises the significant details of the original construction and looks in detail at the recent assessment of the span 4 roof and the associated parcel deck. Network Rail, the asset steward, is in the throes of undertaking the first major refurbishment of span 4 for over half a century and the paper describes the main aspects of the investigations and design that have led to the current works.

Wholesale greengrocers and fishmongers market, Bursa, Turkey

This spectacular covered market set in a beautifully landscaped hilltop of the famous Silk Road is composed of two buildings. The central open air courtyard of the greengrocer market is enclosed by oval shaped covered gallery. The fishmonger market is a smaller building set apart. The design of both markets maintains the idea of the grand bazaars, thus connecting the new buildings to the long-standing cultural traditions of Central Asia. But at the same time the steel spanned arched roof provide fully modern qualities such as space, comfort, light and ventilation.

A Study on Adaptive Arch Structure Applying Variable Geometry Truss (Mechanism of Movable Arch Roof with External Panel)

This paper describes a movable arch roof with external panels as an actual design of an adaptive structure using a VGT (Variable Geometry Truss) mechanism comprising an elementary truss structure with extendable members. This movable arch structure comprises several VGT units jointed in series and pin jointed at each end. It is a stable structure because its edge is restrained, but this reduces its variety of shape change. Various arch shapes can be determined by using inverse analysis to solve the structure shape from the member lengths. An actual movable roof pavilion composed of such a movable arch and an external panel was designed, and the behaviors of a movable roof and the joint mechanism of the roof elements were verified by numerical simulation and a model experiment. As a result, the performance of the proposed movable roof structure was confirmed, and the basic technology and design approach were established.

VIBRATION TESTS ON SEISMIC RESPONSES OF ARCH STRUCTURES SUPPORTED BY SUBSTRUCTURES WITH VARIOUS NATURAL PERIODS AND MASSES

Seismic response of arch structures with supporting substructures is known to be amplified in vertical directions even under horizontal input, and their amplitude changes along the relationship between mechanical properties of roofs and substructures. Although a large number of studies on seismic response behavior by numerical analyses have been made, seismic response behavior by vibration test has not been sufficiently investigated. In this paper, seismic vibration tests are carried out using small scale arch roof models with supporting substructure in order to confirm influence by the relationship between mechanical properties of roofs and substructures. The validity of response evaluation method proposed in previous papers is examined.

2P1-B14 可変形状トラスを用いた可動型屋根構造に関する研究 : 第8報、アーチ型可動屋根の外装機構とモデル実験(建設・解体ロボット・メカトロニクス)

2P1-B14 可変形状トラスを用いた可動型屋根構造に関する研究 : 第8報、アーチ型可動屋根の外装機構とモデル実験(建設・解体ロボット・メカトロニクス)