Now, procedures of design for the earthquake resistance of buildings and non-building structures SNI 1726: 2012 has been approved the procedures for seismic design for buildings SNI 1726-2002. SNI 1726: 2012 refers to the development of modern seismic regulations are due to changes in tectonic plates located on the active track on the path of circum-Pacific and the Indian track - the Himalayas. With the enactment of the new SNI earthquake, namely SNI 1726: 2012, then all existing buildings and designed with old SNI earthquake, that is SNI - 1726-2002 should be evaluated against for the new regulations. Handling scheme for existing buildings should be made to determine and improve safety. Analysis and solutions are required to improve the safety of buildings. Retrofitting Seismic Isolation is one of the effective and practical methode to increase safety of buildings against earthquakes, because this methode can reduce the earthquake acceleration response. Retrofitting seismic isolation can not only improve the safety and functionality seismic, but also to maintain the original design. Without the need to demolish and rebuild the building, the building will remain intact. So that historic buildings and cultural heritage can still be preserved. The concept of base isolation is to decouple the upper structure from its foundation and inserting isolator which has a small horizontal stiffness. This techniques can reducing the seismic impact from the soil vibration which could be from seismic motion. This study will compare the ratio building safety for old structural design that uses SNI-1726-2002 (old) vs SNI 1726: 2012 (new). The results shows that retrofitting seismic isolation building have better performance in terms of ductility demand, natural period, and lower internal forces due to earthquake.

Submerged Floating Tunnels (SFT) is a tubular structure that is submerged and floating in depth remains through the system of anchors consisting of a cable connected to the seabed. SFT structure imposed its own weight and is assisted by the buoyancy or uplift caused by water, cross sectin of the tunnel is designed so that buoyancy can overcome the structural weight and experienced a lift force that causes the floating structure. Fastening system (mooring system) also play a role which is to inhibit the SFT structure, minimize displacement and stress caused by environmental burden, such as earthquakes and hydrodynamic load that can aggravate the condition SFT structure in case of crossing the sea with SFT system. SFT will give a fairly small impact on the environment as it floated in the water, and with built using a modular system, the SFT (Submerged Floating Tunnels) can reach a distance long enough and does not cause pollution. Basically the same as the force that occurs archimides principle, where the objects are in the water to get a compressive force to the top. Cross sectional analysis SFT, will be modeled by 7 different models that have been in previous studies. The model's of SFT with steel cable to hold the structure in order to remain strong with the inclination selected. Analysis is done by modeling the triangle wiring configuration with different angle of incliflation cable. The analysis by comparing the test model were made earlier with prototype analyzed numerically. The expected structure did not undergo excessive deformation due to the environmental burden. Therefore, the structure of the SFT will be done with the Abaqus as finite element analysis. So, obvious deformation occurred in the cable. Therefore, it was expected to obtain the optimum angle of inclination was 54º.