Load Analysis on LPMP Makassar Buildings By Using Static and Dynamic

Indonesian territory which consists of several islands, both large and large and small, is an area that has a level of vulnerability. In this case heard and witnessed through the media various events from natural phenomena, namely earthquakes in recent years that hit several regions in Indonesia. The potential for natural phenomena to occur is very large because the position of the Indonesian archipelago is at the confluence of the Australian plate, the Pacific plate, and the Eurasian plate. This condition causes the need to comply with the principles of planning and implementing an earthquake resistant system in every building structure to be built in the territory of Indonesia, especially for areas that have a moderate to high level of earthquake risk or vulnerability. Research on the main structure of the LPMP office building with 8 floors aims to determine the behavior of the structure in response to static earthquake loads and dynamic earthquake loads. The method suitable for building design involving earthquake loads in the calculation is the equivalent static. This method is only intended for regular horizontal and vertical SNI 1726(2012)buildings. One of the characteristics of a regular bulding is that the building’s height is less than 40 meters and 10 levels as seen from the building pedestal so that the building tends to be rigid and the building is low. Along with the development of the times, many software that can be used to facilitate an earthquake resistant building design in Indonesia have been revised to SNI-1726(2012). In earthquake SNI 03-1726-2012 article 7.1.3 it is stated that : the final value of the dynamic response of the building structure to the nominal earthquake loading due to the effect of a planned earthquake in a certain direction, should not be taken less than 85 % of the value of the first variety response. If the dynamic response of the building structure is expressed in nominal basic shear force V, where the value of the oh the nominal base shear for each static earthquake in the x direction is 0.867622 and the y direction is 0.975368 where the bigger the dynamic earthquake in the x direction is 3425.624 and the y direction amounting to 3550.92 so that the structural seismicity review shows the result that meet the seismic requirements stipulated in the SNI, starting from the building period, the mass participation ratio, the basic shear force of structural deviations.

Baroclinic Instability of Nonzonal Flows and Bottom Slope Effects on the Propagation of the Most Unstable Wave

A linear, two-layer potential vorticity (PV) equation model on the β plane is employed to study the baroclinic instability of nonzonal basic currents flowing over a uniform bottom slope. Criteria for the instability, phase speed, and growth rate of unstable waves are all given as functions of the basic shear velocity, β, and bottom slope. The study suggests two kinds of long wave cutoff, one induced by the slope and the other by β; the first one exists in all directions, while the second requires at least a slight deviation of the wave vector from the meridians. Subtle differences between configurations of the PV gradient lead to completely different characteristics of unstable perturbations, such as propagation and scale. In the case of a positive slope (the bottom slope in the same direction as the isopycnal tilt), the fastest-growing wave is capable of propagating across the basic flow streamlines. By contrast, in the case of a negative slope (the bottom slope opposed to the isopycnal tilt), the most unstable wave always propagates along the streamlines. In addition, the spatial scale of the most unstable mode can be heavily reduced by a negative slope.

Global stability of buoyant jets and plumes

The linear global stability of laminar buoyant jets and plumes is investigated under the low-Mach-number approximation. For Richardson numbers in the range $10^{-4}\leqslant Ri\leqslant 10^{3}$ and density ratios $S=\unicode[STIX]{x1D70C}_{\infty }/\unicode[STIX]{x1D70C}_{jet}$ between 1.05 and 7, only axisymmetric perturbations are found to exhibit global instability, consistent with experimental observations in helium jets. By varying the Richardson number over seven decades, the effects of buoyancy on the base flow and on the instability dynamics are characterised, and distinct behaviour is observed in the low-$Ri$ (jet) and in the high-$Ri$ (plume) regimes. A sensitivity analysis indicates that different physical mechanisms are responsible for the global instability dynamics in both regimes. In buoyant jets at low Richardson number, the baroclinic torque enhances the basic shear instability, whereas buoyancy provides the dominant instability mechanism in plumes at high Richardson number. The onset of axisymmetric global instability in both regimes is consistent with the presence of absolute instability. While absolute instability also occurs for helical perturbations, it appears to be too weak or too localised to give rise to a global instability.

Experimental Tests on Steel Buckling Inhibited Shear Panels

Passive protection systems based on the use of metal shear panels represent an effective way for achieving a significant improvement of the seismic response of buildings. Nevertheless, the dissipative capacity of these devices could be limited by buckling phenomena. In order to reduce the influence of instability, "Buckling Inhibited Shear Panels" have been recently introduced as an innovative and convenient solution. It is based on the use of steel plated elements able to restrain out-of-plane displacements of the basic shear plate but without any type of interactions in terms of membrane strains. In this paper the outcomes of an extensive experimental campaign on the proposed system are shown. The tested coupons are made of steel and are characterized by two different thicknesses. Moreover, two technologies for the inhibition of buckling phenomena are examined. The former is able to contain the out-of-plane displacements for the only plate portions that are most involved in the development of the first critical modes. The latter, with a more complex assemblage of the parts, is obtained by inhibiting the out-of-plane deformations of the whole system. The results obtained, compared to the ones given by only steel plates without buckling restraining devices, allow to highlight the increase in terms of energy dissipation capacity that is possible to achieve through the proposed technologies, also evidencing some critical issues that can arise when little accuracy in the assembly of the system is spent.

Waves and resonance in free-boundary baroclinic instability

Eady's model of baroclinic instability has been generalized by including β (the meridional gradient of planetary potential vorticity) while assuming that total potential vorticity is uniform. Moreover, the problems of Eady and of Phillips have been enriched by including a fixed topography or a free boundary (which implies a flow-dependent geostrophic topography). The most general cases (with β, fixed topography and a free boundary) of both problems are shown to have nearly identical stability properties, mainly determined by two Charney numbers: the planetary one and a topographic one. The question of whether this generalized baroclinic instability problem can be described by wave resonance or component ‘resonance’ is addressed. By waves are meant physical modes, which could freely propagate by themselves but are effectively coupled by an independent basic shear, producing the instability. Components, on the other hand, are mathematical modes for which the shear is also crucial for their existence, not just for their coupling, hence the quotation marks around ‘resonance’. In this paper it is shown that both scenarios, components ‘resonance’ and waves resonance, cast light on the free-boundary baroclinic instability problem by providing explanations of the instability onset (at minimum shear) and maximum growth rate cases, respectively. The importance of the mode pseudomomentum for the fulfillment of both mechanisms is also stressed.

The long-wave instability of a defect in a uniform parallel shear

The stability properties of an inviscid, parallel, incompressible, free shear flow are studied. The shear profile is that of an unbounded, plane Couette flow containing a defect, or transition zone, whose magnitude ε is assumed to be small. The linearized eigenvalue problem is solved first for discretized models. When the defect has a finite thickness, the instability is confined to longitudinal wavenumbers, k [les ] 0(ε), in contrast to the more common 0(1) bandwidth, in units of inverse shear length. This observation motivates the application of a long-wave expansion to a smooth defect profile. A double expansion in both k and ε captures the whole waveband of the instability, and yields convergent expansions for the unstable eigenfunctions and for the dispersion relation describing their growth rate. The fastest growing modes are determined, and their back-reaction on the basic shear is calculated.

Evolution of wavelike disturbances in shear flows : a class of exact solutions of the Navier-Stokes equations

New classes of exact solutions of the incompressible Navier-Stokes equations are presented. The method of solution has its origins in that first used by Kelvin ( Phil. Mag . 24 (5), 188-196 (1887)) to solve the linearized equations governing small disturbances in unbounded plane Couette flow. The new solutions found describe arbitrarily large, spatially periodic disturbances within certain two- and three-dimensional ‘ basic ’ shear flows of unbounded extent. The admissible classes of basic flow possess spatially uniform strain rates; they include two- and three- dimensional stagnation point flows and two-dimensional flows with uniform vorticity. The disturbances, though spatially periodic, have time-dependent wavenumber and velocity components. It is found that solutions for the disturbance do not always decay to zero ; but in some instances grow continuously in spite of viscous dissipation. This behaviour is explained in terms of vorticity dynamics.

Instabilities of dynamic thermocapillary liquid layers. Part 2. Surface-wave instabilities

A planar liquid layer is bounded below by a rigid plate and above by an interface with a passive gas. A steady shear flow is set up by imposing a temperature gradient along the layer and driving the motion by thermocapillarity. This dynamic state is susceptible to surface-wave instabilities that couple the interfacial deflection to the underlying shear flow. These instabilities are found to be directly related to the two-dimensional waves on an isothermal layer subject to wind shear as described by Miles and by Smith & Davis. Hence the surface-tension gradients are important only in that they drive the basic shear flow. The surface-wave stability characteristics for liquid layers with and without return-flow profiles are presented, and special attention is paid to long-wave instabilities. Comparisons are made with available experimental observations.