Earthquakes, Records, and Nonlinear Responses

1998 ◽  
Vol 14 (3) ◽  
pp. 469-500 ◽  
Author(s):  
Nilesh Shome ◽  
C. Allin Cornell ◽  
Paolo Bazzurro ◽  
J. Eduardo Carballo
Keyword(s):  
Earth Quake ◽  
Structural Response ◽  
Steel Structure ◽  
Lower Intensity ◽  
Nonlinear Analyses ◽  
Nonlinear Responses ◽  
Annual Probability ◽  
Proper Scaling ◽  
Global And Local ◽  
Nonlinear Structural Response

The estimation of MDOF nonlinear structural response given an earth-quake of magnitude M at distance R is studied with respect to issues such as the benefits and harms of (1) first scaling the records, (2) selecting records from the “wrong” magnitude, (3) alternative choices for how to scale the records, and (4) scaling records to a significantly higher or lower intensity, etc. We find that properly chosen scaling can reduce the necessity of the number of nonlinear analyses by a factor of about four, and that proper scaling does not introduce any bias. Several global and local nonlinear damage measures are considered. A five-DOF model of a steel structure is used; other cases are under study. The paper finishes with a demonstration of the use of such results in the estimation of the annual probability of exceeding a specified interstory ductility (drift) or other damage measures.

Numerical Analysis of Fire Behavior of a Large Space Pre-Stressed Steel Structure under Fire

2011 ◽  
Vol 71-78 ◽  
pp. 3729-3732
Author(s):  
Ming Zhou ◽  
Zhi Guo Xie ◽  
Xin Tang Wang
Keyword(s):  
Numerical Analysis ◽  
Fire Behavior ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Large Space ◽  
Fire Source ◽  
Lattice Shell ◽  
In Fire ◽  
Influence Degree

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.

scholarly journals Hemp Cables, a Sustainable Alternative to Harmonic Steel for Cable Nets

Resources ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 70 ◽  
Author(s):  
Alberto Viskovic
Keyword(s):  
Three Dimensional ◽  
Structural Response ◽  
Building Design ◽  
Structural Elements ◽  
Nonlinear Analyses ◽  
Hyperbolic Paraboloid ◽  
Materials Engineering ◽  
Recent Developments ◽  
Vertical Displacements ◽  
Cable Nets

Recent developments in the field of materials engineering have allowed for the use of natural materials for common structural elements, instead of traditional materials, such as steel or concrete. In this context, hemp is a very interesting material for structural building design. This paper proposes the use of hemp cables for roofs with hyperbolic paraboloid cable nets, which sees the use of a sustainable material for structure, thus having a very low environmental impact, in terms of structural thickness and amount of material. The paper discusses five different plan sizes and two different hyperbolic paraboloid surface radius of curvatures. The cable traction, which gives the cable net stiffness, was varied in order to give a parametric database of structural response. Three dimensional geometrically nonlinear analyses were carried out on different geometries (i.e., 10), cable net stiffnesses (i.e., 8), and materials (i.e., 2). Traditional harmonic steel and hemp cables are compared, in terms of vertical displacements and natural periods under dead and permanent loads.

scholarly journals Nonlinear Response of High Arch Dams to Nonuniform Seismic Excitation Considering Joint Effects

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Masoomeh Akbari ◽  
Mohammad Amin Hariri-Ardebili ◽  
Hasan Mirzabozorg
Keyword(s):  
Structural Response ◽  
Incompressible Material ◽  
Arch Dam ◽  
High Arch Dam ◽  
Arch Dams ◽  
Base Level ◽  
Nonlinear Responses ◽  
Wave Passage ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying

Nonuniform excitation due to spatially varying ground motions on nonlinear responses of concrete arch dams is investigated. A high arch dam was selected as numerical example, reservoir was modelled as incompressible material, foundation was assumed as mass-less medium, and all contraction and peripheral joints were modelled considering the ability of opening/closing. This study used Monte-Carlo simulation approach for generating spatially nonuniform ground motion. In this approach, random seismic characteristics due to incoherence and wave passage effects were investigated and finally their effects on structural response were compared with uniform excitation at design base level earthquake. Based on the results, nonuniform input leads to some differences than uniform input. Moreover using nonuniform excitation increase, stresses on dam body.

Shake Table Testing of a Low Damage Steel Building with 2-4 Displacement Dependent (D3) Viscous Damper

2018 ◽  
Vol 763 ◽  
pp. 331-338
Author(s):  
Nikoo K. Hazaveh ◽  
Ali A. Rad ◽  
Geoffrey W. Rodgers ◽  
J. Geoffrey Chase ◽  
Stefano Pampanin ◽  
...  
Keyword(s):  
Viscous Fluid ◽  
Residual Deformation ◽  
Structural Response ◽  
Steel Structure ◽  
Experimental Tests ◽  
Base Shear ◽  
Moment Frame ◽  
Fluid Damper ◽  
Resistive Forces ◽  
Viscous Fluid Damper

To improve seismic structural performance, supplemental damping devices can be incorporated to absorb seismic response energy. The viscous fluid damper is a well-known solution. However, while they reduce displacement demand, they can increase overall base shear demand in nonlinear structures as they provide resistive forces in all four quadrants of force-displacement response. In contrast, Direction and Displacement Dependent (D3) viscous fluid dampers offer the opportunity to simultaneously reduce structural displacements and the total base-shear force as they only produce resistive forces in the second and fourth quadrants of a structural hysteresis plot. The research experimentally examines the response of a half-scale, 2-storey moment frame steel structure fitted with a 2-4 configuration D3 viscous fluid damper. The structure is also tested with conventional viscous dampers to establish a baseline response and enable comparison of results. Dynamic experimental tests are used to assesses the base shear, maximum drift and residual deformation under 5 different earthquakes (Northridge, Kobe, Christchurch (CCCC), Christchurch (CHHC), and Bam ground motion). Response metrics including base shear, the maximum structural displacement, and peak structural accelerations are used to quantify performance and to assess the response reductions achieved through the addition of dampers. It is concluded that only the 2-4 device is capable of providing concurrent reductions in all three of these structural response metrics.

scholarly journals Real Cyclic Load-Bearing Test of a Ceramic-Reinforced Slab

2020 ◽  
Vol 10 (5) ◽  
pp. 1763
Author(s):  
Albert Albareda-Valls ◽  
Alicia Rivera-Rogel ◽  
Ignacio Costales-Calvo ◽  
David García-Carrera
Keyword(s):  
Cyclic Load ◽  
Structural Response ◽  
Steel Structure ◽  
Steel Beams ◽  
Load Bearing ◽  
Rc Frames ◽  
Industrial Buildings ◽  
Loading And Unloading ◽  
Low Levels ◽  
The City

Ceramic-reinforced slabs were widely used in Spain during the second half of the 20th century, especially for industrial buildings. This solution was popular due to the lack of materials at that time, as it requires almost no concrete and low ratios of reinforcement. In this study, we present and discuss the results of a real load-bearing test of a real ceramic-reinforced slab, which was loaded and reloaded cyclically for a duration of one week in order to describe any damage under a high-demand loading series. Due to the design of these slabs, the structural response is based more on shear than on bending due to the low levels of concrete and the geometry and location of re-bars. The low ratio of concrete makes these slabs ideal for short-span structures, mainly combined with steel or RC frames. The slab which was analyzed in this study covers a span of 4.88 m between two steel I-beams (IPN400), and corresponds to a building from the mid-1960s in the city of Igualada (Barcelona, Spain). A load-bearing test was carried out up to 7.50 kN/m2 by using two-story sacks full of sand. The supporting steel beams were propped up in order to avoid any interference in the results of the test; without the shoring of the steel structure, deflections would come from the combination of the ceramic slab together with the steel profiles. A process of loading and unloading was repeated for a duration of six days in order to describe the cyclic response of the slab under high levels of loading. Finally, vibration analysis of the slab was also done; the higher the load applied, the higher the fundamental frequency of the cross section, which is more comfortable in terms of serviceability.

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