Elastic design response spectra

Seismic Response Spectrum

Most seismic design is based on representing the earthquake actions in the for of an equivalent static force applied to the structure. hese forces are determined from the maximum acceleration response of the structure under the expected earthquake-induced ground shaking, hich is represented by the acceleration response spectrum. The starting point is an elastic response spectrum, which is subsequently reduced by factors that account for the capacity of the structure to dissipate the seismic...

Seismic Load Combinations Eurocode

Seismic Capacity Design Chain

The radius of gyration, l, is the square root of the ratio of the polar moment of inertia to the mass, the polar moment of inertia being calculated about the centre of mass. For a rectangular building of side lengths l and b, and a uniform mass distribution, Equation 4.3 applies. The requirement for torsional radius r to exceed 3.33 times the mass-stiffness eccentricity e item 5 on the list at the beginning of this section relates the torsional resistance to the driving lateral-torsional...

Manual For Seismic Design Afps

Figure 4.8 Structural layout taken for regularity checks The floor slabs in the tower are rectangular, without branches, and have an aspect ratio in the tower see 4 below of 56 m 20 m 2.8, which is relatively compact. Given the uniform distribution of mass and lateral load resisting elements i.e. the frames and shear walls in the long direction, a continuous concrete solid slab or topping slab over precast elements of at least 70 mm would not be expected to give rise to uneven load...

Design example on a pile foundation

Borehole Data For Pile Foundation

In this section e shall outline the design of a pile foundation for a typical column of the building for which the seismic designs were carried out in earlier chapters. f course in reality the design of pile foundations ill be carried out for individual columns with the associated reductions in the pile lengths and or pile diameters to suit the design load on the column. Here we shall only consider one typical column along the D line on the plan of the building. Another premise that is made...

Moment Resisting Frame

Steel Concentric Braced Frames

Investigated by several researchers e.g. Lay and Galambos, 1967 Kato and Akiyama, 1982 Kato, 1989 . In subsequent sections, the behaviour of the three ain configurations of steel frame structure, namely moment resisting, concentrically and eccentrically braced frames, is discussed. Whereas moment-frames exhibit relatively ductile behaviour under earthquake loading, their lo lateral stiffness may, in some situations, result in high storey drifts, thus leading to unacceptable damage to...

Design example moment frame Introduction

The same eight-storey building considered in previous chapters is utilised in this example. The layout of the structure is reproduced in Figure 6.17. The main seismic design checks are carried out for a preliminary design according to EN 1998-1. For the purpose of illustrating the main seismic checks in a simple manner, consideration is only given to the lateral system in the X-direction of the plan, in which resistance is assumed to be provided by MRFs spaced at 4 m. It is also assumed that an...

Typical Column Details

Typical Column Details

Critical Region for full length of short column lc hc lt 3 Critical Region Prescriptive Confinement to clauses 5.4.3.2.2 1 to 4 , 10 and 11 . Critical Region prescriptive Confinement to dauses 5.4.3.2.2 1 to 4 , 10 and 11 . Reduced confinement away from plastic hinge zones. All column splices within this region. Beam Column Joint 'Special' Confinement to clauses 5,4,3,3 fl to 3 Figure 5.8 Typical column details - elevation where wd is volume of confining hoopsf Avolume of concrete core , bQ is...

Pile Foundation Failure

Pile Failure Earthquake Liquefaction

Pile foundations are widely used both onshore and offshore to transfer heavy structural loads to copetent load bearing soil strata or bedrock. eotechnical engineers are called upon to design deep foundations hen the shallo layers of soils beneath the building are either unable to support the loads iposed by the superstructure on the shallo foundations or if the shallow layers may become unstable due to the cyclic shear stresses induced by the earthquake loading. Under such circumstances it is...

Standardisation of seismic design

The first concepts for structural design in seismic areas, the subject of Eurocode 8 (EC8), were developed from experience gained in catastrophes such as the San Francisco earthquake in 1906 and the Messina earthquake in 1908. At the very beginning, in the absence of experimental data, the method used was to design structures to withstand uniform horizontal accelerations of the order of 0.1g. After the Long Beach earthquake in 1933, the experimental data showed that the ground accelerations...