[Updated on 14-Jan] The SEWC2011 Organizing Committee apologizes for the not yet defined status of the abstracts which still are labelled AD (awaiting decision); the Scientific Committee will clear the positions as soon as possible and will postpone the submittal of the final accept paper until February 15th, 2011.

PARTIAL LIST OF ACCEPTED ABSTRACTS (as of JAN 04, 2011)

ID: 2 Nonlinear halfspace contact
ID: 7 Influence Of The Humidity On Compressive Strength Of Sand Concrete
ID: 11 Analytical Modeling of Bond Slip Responses in Reinforced Concrete Structural Columns
ID: 13 "ANALYSIS AND DESIGN OF LONG-SPAN CABLE- MEMBRANE STRUCTURES INTEGRATED WITH SUPPORTED STRUCTURE"
ID: 15 STUDY OF PERVIOUS CONCRETE MADE OF AGGREGATES RECYCLED FROM DEMOLISHED CONCRETE WASTES
ID: 16 Computer Modelling and Seismic Performance Assessment of a Gothic Cathedral in Cyprus
ID: 18 Wind-induced Vibrating Serviceability Analysis of a Long Span Sightseeing Bridge Based on Wind-tunnel Test
ID: 22 Research on Adhesive Strength of Concrete Placing Joint Plain
ID: 23 Impact Performance and Strengthening of Frontal Columns
ID: 26 Experimental investigation into the performance of concrete beams with rectangular openings strengthened in shear with CFRP composites
ID: 28 Strengthening of Reinforced Concrete Columns Subjected to Biaxial Eccentric Loading with NSM Composite System
ID: 30 Structural Design of the Building with Seismic-Response Controlled System
ID: 33 Global and Local Design Methods for the Architectural Complex of the Large Base Multi-high Story Group Buildings
ID: 34 Design issues and construction method of a new concrete railway bridge over the Swiss A2 motorway in Camorino (Alptransit Lot 771)
ID: 35 CORE ECCENTRICITY IMPACT ON THE STRUCTURAL BEHAVIOUR AND FOUNDATIONS OF CONCRETE TALL BUILDINGS
ID: 36 WIND RESPONSE STUDY FOR LOW/MEDIUM/HIGH RISE CONCRETE BUILDINGS IN GCC COUNTRIES
ID: 39 Using Fuzzy Logic (FL) to Find Crack Pattern in Strengthened RC Slab
ID: 41 High-rise Seismic-isolated Building With Tension rod frames - Rokin Higobashi Building -
ID: 50 Structural Design of the Kaohsiung Stadium
ID: 52 Can glass compete with acrylics on large aquaria enclosures ?
ID: 53 High Strength SFRC: Pure Torsion
ID: 56 INERD software: a new design tool to improve the robustness of RCMRF under Earthquake loading
ID: 58 Form Finding for the ROLEX LEARNING CENTER at EPFL Lausanne
ID: 59 Construction of the ROLEX LEARNING CENTER at EPFL Lausanne
ID: 60 Influence Of The Humidity On Compressive Strength Of Sand Concrete
ID: 61 APPLICATION OF ACTIVE BASE ISOLATION SYSTEM USING ABSOLUTE VIBRATION CONTROL TECHNOLOGY
ID: 66 An investigative study on the effects of silica flour, zeolite and silica fume on the durability of roller compacted concrete
ID: 67 Nonlinear earthquake response analysis of RC frame and steel plate shear wall structure
ID: 68 Tensile Test of Reinforced Ultra High Performance Concrete Prismatic Bars
ID: 69 Performance of steel frames with various buckling modes in the braces
ID: 71 Nonlinear Analysis of Bolted Beam-Column Connection
ID: 72 Low Cost green housing for India’s rural masses
ID: 73 Development of Direct Displacement Based Design software
ID: 82 High performance concrete for sustainable construction
ID: 84 A novel method of analyzing structures: Total Potential Optimization Method
ID: 90 Long term effects on unbonded post-tensioned timber beams
ID: 91 Numerical study on the seismic interaction between 2D seismic resisting frames and claddings
ID: 92 Numerical modelling and preliminary experimental testing outcomes for the design of seismic resistant facades
ID: 94 Recent Examples of Cable Structures -Design and Construction Focused on Initial Tensile Force-
ID: 97 Seismic Retrofit of High-rise Building With Deformation-Dependent Oil Dampers
ID: 100 Behavior of RC membranes having different steel arrangements
ID: 101 Analysis for Erection Process and Construction of Tension Structures
ID: 103 Study on the way of Building Construction in Sustainable Society
ID: 104 Lightweight sandwich slabs consisting of an ALC core adhesively bonded with steel skins
ID: 106 Ice Shell Construction in Hokkaido
ID: 107 Comparison of the Analytical Models to Determine Modulus of Elasticity of Self-Compacting Concrete and Conventional Concrete
ID: 109 Evaluation and Comparison of the Analytical Models to Determine Tensile Strength of Self-Compacting Concrete and Conventional Concrete
ID: 110 Evaluation and Comparison of the Analytical Models to Predict Creep and Shrinkage Behaviour of Self-Compacting Concrete
ID: 111 DEVELOPMENT AND APPLICATIONS OF GLASS FIBER BARS AS A FRAME IN CONCRETE STRUCTURES
ID: 112 Composite steel-glass fins for the lobby façade of Iberdrola Tower
ID: 113 Formulation of a Direct Displacement-Based Seismic Design Procedure for Steel Moment-Resisting Frame Structures
ID: 114 Bond Performance of Reinforced Concrete Beams with Electric Arc Furnace Oxidizing Slag Aggregates
ID: 115 High Damping Rubber Bearing (HDRB) isolating devices for nuclear power plants: FE modelling and damage/failure characterization
ID: 119 Prefabricated stabilising walls for multi-storey timber buildings - general concepts and preliminary design
ID: 120 Shock Transmitters application to a reinforced concrete precast building
ID: 122 Seismic Vulnerability Assessment of a reinforcement concrete strategic building ,gravity load designed, site in Teramo - Italy
ID: 123 A new derivation for the equations of influence line of moment at supports for indeterminate continuous beams and rigid frames
ID: 124 Limit analysis of rigid block models for reinforced concrete frames under lateral loads
ID: 125 A study on reinforcement of existing RC beam -for reuse of underground structure-
ID: 127 Experimental Investigation on the Stiffness of Beam-Column Connections in Post-Tensioned Timber Frames
ID: 129 Experimental investigation on connections between wood framed shear walls and foundations
ID: 130 Sheathing to framing connections: experimental and numerical analysis
ID: 131 Experimental investigation of the behaviour of different type of connections between the XLAM panels and the concrete slab
ID: 133 Long-term Performance Test of Laminated Rubber Bearing for Seismic Isolation System
ID: 134 Determination of interfacial transition zone in cementitious materials by dynamic displacement
ID: 135 Comparison of static elasticity modulus of Conventional and Self-Compacting Concrete
ID: 139 An experimental investigation on the effect of pozzolan and s12 on durability of roller compacted concrete.
ID: 145 Seismic design of buckling restrained braced frames with reduced core length
ID: 146 Design of High-rise Base Isolated Structure with a complex shape and long span
ID: 147 Strength of R/C arch subjected to several loading
ID: 148 Influences of changing rigidity center with vibration on earthquake resistance of the steel frame with different hysteresis model
ID: 150 Construction of Civil Building Using Three-dimensional Seismic Isolation System
ID: 151 Modularization why,where,how
ID: 155 Post-tensioning in timber slabs
ID: 156 Simplified design tools for post-tensioned timber beams and walls
ID: 157 Effect of Tunnel Induced Settlements on the Earthquake Resistance Capacity of Concrete Frame Buildings
ID: 159 Nonlinear finite element modelling for thick-walled reinforced concrete pipe
ID: 160 Application of post-tensioning techniques to pedestrian timber bridges
ID: 161 Influence of Low Pull-Off Strength of Concrete on FRP Reinforcement of R.C. Slabs of Railway Bridges
ID: 167 Bond Stress in Concrete-Filled Steel Tube Column with High Strength Steel and Concrete
ID: 169 Evaluation of stability of sacral and historical towers depending on seismic zone
ID: 170 ON THE RETROFIT AND THE NUMERICAL INVESTIGATION OF THE PANTOCRATOR CISTERN
ID: 171 About Structural Engineering & Sustainability
ID: 173 The “SPHERE” for Deutsche Bank, Frankfurt
ID: 175 Shear Behavior of Composite Concrete/GFRP Beams
ID: 177 Deflection of Reinforced Concrete Beams Simultaneously Subjected to Sustained Load and Reinforcement Corrosion
ID: 178 ARCHITECTURE TOWARDS SEISMIC ENGINEERING
ID: 179 Constitutive model for Slurry Infiltrated Fiber Concrete under triaxial compression
ID: 184 Seismic performance and retrofitting of precast industrial buildings
ID: 185 Seismic retrofitting strategies for an under-designed R/C structure
ID: 187 Prediction of Flexure Extension on Maximum Flexure Load on the RC Slab Using ANNs & FL
ID: 188 An Investigative Study on the Effects of Nano-SiO2 on Compressive Strength and Permeability of Concrete
ID: 189 Conceptual Design of Hybrid String Structures
ID: 190 Hysteresis response of T type RC frame with self-centering structure
ID: 192 Concept of Incremental stiffness for buildings using displacement compatibility
ID: 194 Applications of Special Concrete in Modern Marine Structures
ID: 198 Influence of Slipping of the Nailed Steel-to-Timber Connections on the Dimensioning of the Timber Trusses Systems
ID: 199 Glulam Pitched Cambered and Curved Beams - Analysis of Slope and Geometry of Apex Zone Effects on their Practical Application
ID: 200 End Notched Wooden Beams and Wooden Beams with Holes - Fracture models and Analysis of Crack Propagation
ID: 202 Dimensions of coupling beams effects on behaviour of coupled concrete bearing walls
ID: 204 Computational Morphogenesis and Optimization in Structural Engineering and Architecture
ID: 208 ECO-CONSCIOUS APPROACH TO INNOVATIVE STRUCTURAL FORMS FOR TALL BUILDINGS
ID: 213 MODELLING OF THE DAMAGE EVOLUTION OVER TIME OF JOINTS AND MORTAR/BRICK INTERFACES UNDER SALT CRYSTALLISATION TESTS
ID: 214 Methodology for on site evaluation of physical and mechanical properties of historic masonry
ID: 216 OPERATIONAL MODAL TESTING AND ANALYSIS OF BRIDGES
ID: 217 DYNAMIC MEASUREMENT ON HISTORIC MASONRY TOWERS USING AN INTERFEROMETRY RADAR SYSTEM
ID: 218 DYNAMIC ASSESSMENT AND HEALTH MONITORING OF AN HISTORIC IRON ARCH BRIDGE
ID: 220 Numerical modelling of the Armstrong, Mitchell & Co. hydraulic crane of the Arsenal of Venice
ID: 230 A KNOWLEDGE BASED APPROACH FOR THE DEFINITION OF STRENGTHENING SOLUTIONS ON CULTURAL HERITAGE BUILDINGS IN L’AQUILA (ITALY) AFTER THE 2009 EARTHQUAKE
ID: 231 The Spanish Fortress in l’Aquila: emergency actions, investigations and monitoring
ID: 232 NEW INTEGRATED KNOWLEDGE BASED APPROACHES TO THE PROTECTION OF CULTURAL HERITAGE FROM EARTHQUAKE-INDUCED RISK
ID: 245 New Configurations for Double-Layer Tensegrity Grids
ID: 246 Deployment aspects of a tensegrity-ring pedestrian bridge
ID: 247 Active Member Configuration for Damage Tolerance of a Deployable Tensegrity Bridge
ID: 252 Design and Analysis of Tensegrity Power Lines
ID: 253 Application of Flexibility Analysis for Design of Tensegrity Structures
ID: 258 Mechanical behaviour of a foldable tensegrity ring: parametric study
ID: 261 Space structures from aperiodic patterns - application of Ammann bar grids concept
ID: 262 Generation of structural lattices by means of multiplication of planar graphs
ID: 263 A special case of a non-developable surface and its applications
ID: 264 Proposition of an index description system for geometric and mechanical properties of spatial tensegrity structures
ID: 267 Lightweight structures - From theory to design
ID: 268 Risk management for investment in commercial objects
ID: 269 Interactive design and dynamic analysis of tensegrity systems
ID: 281 Structural performances of single-layer floating-compression tensegrity domes
ID: 283 Chosen Ideas of Geometrical Shaping of Modular Tensegrity Structures

PARTIAL LIST OF ACCEPTED ABSTRACTS (as of JAN 14, 2011)

ID: 10 Displacement-based seismic performance assessment of stone masonry buildings of NE Pakistan
ID: 16 Computer Modelling and Seismic Performance Assessment of a Gothic Cathedral in Cyprus
ID: 18 Wind-induced Vibrating Serviceability Analysis of a Long Span Sightseeing Bridge Based on Wind-tunnel Test
ID: 22 Research on Adhesive Strength of Concrete Placing Joint Plain
ID: 23 Impact Performance and Strengthening of Frontal Columns
ID: 24 Ultimate load-carrying capacity of Schwedler suspendome
ID: 25 Modelling of fire-induced spalling in concrete structural
ID: 29 Performance based design approach to 300 meter high tower building
ID: 30 Structural Design of the Building with Seismic-Response Controlled System
ID: 33 Global and Local Design Methods for the Architectural Complex of the Large Base Multi-high Story Group Buildings
ID: 34 Design issues and construction method of a new concrete railway bridge over the Swiss A2 motorway in Camorino (Alptransit Lot 771)
ID: 41 High-rise Seismic-isolated Building With Tension rod frames - Rokin Higobashi Building -
ID: 45 Mathematical solution for wave diffraction by a cylindrical inclusion in transversely isotropic media
ID: 47 Seismic motion level of dynamic collapse or limit state deformation for lattice arch and cylindrical roof
ID: 50 Structural Design of the Kaohsiung Stadium
ID: 52 Can glass compete with acrylics on large aquaria enclosures ?
ID: 55 New analytical model for the calculation of steel columns Subjected to localised fire
ID: 56 INERD software: a new design tool to improve the robustness of RCMRF under Earthquake loading
ID: 57 Analysis of steel-framed open car parks under localised fire
ID: 58 Form Finding for the ROLEX LEARNING CENTER at EPFL Lausanne
ID: 59 Construction of the ROLEX LEARNING CENTER at EPFL Lausanne
ID: 61 APPLICATION OF ACTIVE BASE ISOLATION SYSTEM USING ABSOLUTE VIBRATION CONTROL TECHNOLOGY
ID: 66 An investigative study on the effects of silica flour, zeolite and silica fume on the durability of roller compacted concrete
ID: 71 Nonlinear Analysis of Bolted Beam-Column Connection
ID: 72 Low Cost green housing for India’s rural masses
ID: 73 Development of Direct Displacement Based Design software
ID: 74 Structural Design of Stadium Roof in Japan and China
ID: 77 Design and Construction of the Complex-Beam String Structure
ID: 81 A finite element modeling of thermo-hydro-mechanical behavior and numerical simulations of progressive spalling front
ID: 82 High performance concrete for sustainable construction
ID: 83 Comparison of techniques for damage identification based on influence line approach
ID: 94 Recent Examples of Cable Structures -Design and Construction Focused on Initial Tensile Force-
ID: 95 Structural design of Seikei Info Library
ID: 97 Seismic Retrofit of High-rise Building With Deformation-Dependent Oil Dampers
ID: 101 Analysis for Erection Process and Construction of Tension Structures
ID: 102 New Development of Beam String Structures
ID: 106 Ice Shell Construction in Hokkaido
ID: 109 Evaluation and Comparison of the Analytical Models to Determine Tensile Strength of Self-Compacting Concrete and Conventional Concrete
ID: 111 DEVELOPMENT AND APPLICATIONS OF GLASS FIBER BARS AS A FRAME IN CONCRETE STRUCTURES
ID: 112 Composite steel-glass fins for the lobby façade of Iberdrola Tower
ID: 113 Formulation of a Direct Displacement-Based Seismic Design Procedure for Steel Moment-Resisting Frame Structures
ID: 114 Bond Performance of Reinforced Concrete Beams with Electric Arc Furnace Oxidizing Slag Aggregates
ID: 115 High Damping Rubber Bearing (HDRB) isolating devices for nuclear power plants: FE modelling and damage/failure characterization
ID: 117 The “quasi-rigid foundation” approach for the simplified modelling of soil structure interaction problems in structural dynamics
ID: 118 Development, execution and results of on-site test campaign exploiting combined tuned methods with multiple variables for the assessment of cast-in-place concrete strength
ID: 120 Shock Transmitters application to a reinforced concrete precast building
ID: 124 Limit analysis of rigid block models for reinforced concrete frames under lateral loads
ID: 125 A study on reinforcement of existing RC beam -for reuse of underground structure-
ID: 127 Experimental Investigation on the Stiffness of Beam-Column Connections in Post-Tensioned Timber Frames
ID: 130 Sheathing to framing connections: experimental and numerical analysis
ID: 131 Experimental investigation of the behaviour of different type of connections between the XLAM panels and the concrete slab
ID: 133 Long-term Performance Test of Laminated Rubber Bearing for Seismic Isolation System
ID: 134 Determination of interfacial transition zone in cementitious materials by dynamic displacement
ID: 135 Comparison of static elasticity modulus of Conventional and Self-Compacting Concrete
ID: 139 An experimental investigation on the effect of pozzolan and s12 on durability of roller compacted concrete.
ID: 142 An overview on diagrid structures for tall buildings
ID: 143 Bubble frame: assessment of a new structural typology starting from the Water Cube
ID: 144 Form – structure interaction in the contemporary non standard architecture.
ID: 145 Seismic design of buckling restrained braced frames with reduced core length
ID: 147 Strength of R/C arch subjected to several loading
ID: 148 Influences of changing rigidity center with vibration on earthquake resistance of the steel frame with different hysteresis model
ID: 150 Construction of Civil Building Using Three-dimensional Seismic Isolation System
ID: 151 Modularization why,where,how
ID: 158 Geometric design of patched spatial structures via WRD
ID: 159 Nonlinear finite element modelling for thick-walled reinforced concrete pipe
ID: 160 Application of post-tensioning techniques to pedestrian timber bridges
ID: 161 Influence of Low Pull-Off Strength of Concrete on FRP Reinforcement of R.C. Slabs of Railway Bridges
ID: 163 Seismic Isolation as a sustainable design strategy
ID: 167 Bond Stress in Concrete-Filled Steel Tube Column with High Strength Steel and Concrete
ID: 169 Evaluation of stability of sacral and historical towers depending on seismic zone
ID: 171 About Structural Engineering & Sustainability
ID: 173 The “SPHERE” for Deutsche Bank, Frankfurt
ID: 175 Shear Behavior of Composite Concrete/GFRP Beams
ID: 176 Natural Draft Cooling Tower Design and Construction in Germany - Past (since 1965), Present and Future
ID: 177 Deflection of Reinforced Concrete Beams Simultaneously Subjected to Sustained Load and Reinforcement Corrosion
ID: 179 Constitutive model for Slurry Infiltrated Fiber Concrete under triaxial compression
ID: 189 Conceptual Design of Hybrid String Structures
ID: 192 Concept of Incremental stiffness for buildings using displacement compatibility
ID: 194 Applications of Special Concrete in Modern Marine Structures
ID: 202 Dimensions of coupling beams effects on behaviour of coupled concrete bearing walls
ID: 203 Semi-active Systems for the Wind Effects Mitigation of a Suspension Bridge
ID: 205 Roof Structure between Two Buildings in severe earthquake prone Country
ID: 206 Diagrids for structural design and construction of complex-shaped tall buildings
ID: 207 Performance-based fire safety approach – application to open car parks according to the new Italian regulation
ID: 209 Tensile Constitutive Model for Concrete at Elevated Temperatures
ID: 210 FEM modelling of the Paderno d’Adda bridge (Italy, 1889)
ID: 212 On the accuracy of response spectrum analysis in seismic design of concrete structures
ID: 214 Methodology for on site evaluation of physical and mechanical properties of historic masonry
ID: 219 Seismic mitigation of 3d steel structures
ID: 221 Experimental study on seismic retrofitting of multi-leaf stone masonry panels
ID: 222 On-site experimental characterization of multi-leaf stone masonry walls struck by the 6th April 2009 Abruzzo earthquake
ID: 223 A Quantification method of structural robustness
ID: 224 Cyclic behavior of high-redundancy reinforced concrete walls
ID: 225 Research of strength interaction of reinforced concrete members under combined loading
ID: 227 COLLAPSE OF SPATIAL STRUCTURES UNDER SEISMIC LOADS CONSIDERING THE INFLUENCE OF NON-STRUCTURAL ELEMENTS
ID: 228 Characteristics of Curved Surface Sliding Isolators for service and seismic Load Cases
ID: 230 A KNOWLEDGE BASED APPROACH FOR THE DEFINITION OF STRENGTHENING SOLUTIONS ON CULTURAL HERITAGE BUILDINGS IN L’AQUILA (ITALY) AFTER THE 2009 EARTHQUAKE
ID: 231 The Spanish Fortress in l’Aquila: emergency actions, investigations and monitoring
ID: 232 NEW INTEGRATED KNOWLEDGE BASED APPROACHES TO THE PROTECTION OF CULTURAL HERITAGE FROM EARTHQUAKE-INDUCED RISK
ID: 237 A New Spatial Beam Element With Closed Thin-walled Section
ID: 238 Applying a Parallel Particle Swarm Optimizer to Truss Topological Design
ID: 240 Optimum design of outrigger and belt truss systems using genetic algorithm (GA)
ID: 241 Structural analysis programme based on the equivalent column’s method
ID: 242 Wave Induced Vibration Analysis of a Steel Curved Bridge Considering Erosion Effect
ID: 243 The environmental demand for efficient recycling of materials from demolition sites
ID: 245 New Configurations for Double-Layer Tensegrity Grids
ID: 246 Deployment aspects of a tensegrity-ring pedestrian bridge
ID: 248 Testing of elastomeric isolators for nuclear power plants
ID: 252 Design and Analysis of Tensegrity Power Lines
ID: 253 Application of Flexibility Analysis for Design of Tensegrity Structures
ID: 258 Mechanical behaviour of a foldable tensegrity ring: parametric study
ID: 260 Assessment of seismic resistance of Surp Nigogoyas Church under earthquake
ID: 261 Space structures from aperiodic patterns – application of Ammann bar grids concept
ID: 262 Generation of structural lattices by means of multiplication of planar graphs
ID: 263 A special case of a non-developable surface and its applications
ID: 264 Proposition of an index description system for geometric and mechanical properties of spatial tensegrity structures
ID: 267 Lightweight structures - From theory to design
ID: 268 Risk management for investment in commercial objects
ID: 269 Interactive design and dynamic analysis of tensegrity systems
ID: 277 Ice shell construction in Hokkaido
ID: 279 MOSE system: testing on the hinge-connector of the flap gate
ID: 280 Seismic isolation of Brescia-Bergamo-Milano Highway in North Italy with Curved Surface Sliders
ID: 286 A static relaxation algorithm for motion-deformation analysis of construction simulation
ID: 287 Real-Time Seismic Damage Detection of Foundations Using Artificial Neural Networks
ID: 288 Verification of Seismic Evaluation for RC School Buildings
ID: 295 Analytical study on earthquake resistance of ultra high strength reinforced concrete columns containing steel fiber
ID: 303 Analysis on Suspender Replacement Plan of the tied arch Bridge
ID: 304 Effective width of continuous composite girder of arch bridge
ID: 306 Determination of Effective Cable Length in Vibration Frequency Method
ID: 307 Seismic strengthening of brick masonry walls with composites: an experimental study
ID: 313 Analytical study on earthquake resistance of ultra high strength reinforced concrete columns containing steel fiber
ID: 314 Seismic Design of Buckling-Restrained Braced Frames Based on Energy Method
ID: 320 FEM/DEM analysis oh historical masonry arch bridge
ID: 321 Multi-scale analysis of Venice trans-lagoon bridge
ID: 322 Design and Construction of 85M Cantilevered Roof of the Busan Cinema Centre, Rep. of Korea
ID: 323 Pinnacle Lift-up of Burj Khalifa
ID: 324 Numerical investigation of structural pounding of seismically isolated buildings during strong earthquakes
ID: 325 Effects of GFRP and natural fiber reinforced polymer on strengthened RC beam under bending
ID: 328 THE EFFECTS OF EARTHQUAKES HAVING DIFFERENT MAGNITUDES ON THE DYNAMIC BEHAVIOUR OF THE ŞEHZADE MEHMET MOSQUE
ID: 329 The Effects Soil Type on Historic Buildings:Dolmabahce Clock Tower
ID: 330 The presentation of a circular passive energy dissipation device for use in steel braced frames
ID: 334 Wind engineering and structural design of Shanghai tower
ID: 336 Recent applications and practices of roof steel structure of stadiums in China