The destruction of nearshore coastal structures in the tsunami events necessitates the importance of improving the tsunami design guidelines in many countries. ASCE 7-2016 included a separate chapter incorporating all the forces to be considered for designing and construction of the tsunami resilient building. When tsunami bore interacts with the structure, the structure initially experiences bore impact force followed by quasi-static hydrostatic or hydrodynamic force, buoyancy force, the uplift force on slabs, debris impact force, etc depending on the Froude number (Fr) of the flow, flow blockage (frontal area exposed to tsunami bore), presence of nearby structure, openings in the structure, location of the structure. The horizontal force after bore impact is usually defined with the hydrodynamic force equation in which the effect of flow blockage and surrounding obstructions are not considered. The present study aimed towards improving the force equation incorporating the effect of flow blockage, adjacent building and openings in the structure with the help of physical experiments and numerical simulation. The experimental study is conducted with a well-controlled bore generation using high discharge pumps. Numerical simulation is carried out in OpenFOAM by generating tsunami-like bore utilizing interFoam solver. Realizable k-epsilon turbulence model is used as this turbulence model is proved to better replicate the experimental results.