TIDES provides structural analysis due to dynamic loading such as equipment and earthquake excitation. We use analytical methods such as response spectrum analysis, modal analysis and time history analysis using computer software.

Frequency domain or known as response spectra analysis tends to be the most cost effective, as they require the least computational effort. Frequency domain analysis includes mode extraction and modal response, and harmonic analysis. Mode frequency analysis will identify the natural frequencies of structures and their sub systems, to allow analysis of the expected response of a structure. Once natural frequencies are known, areas of possible interaction and resonance can be isolated and modified if necessary. Applying a response spectrum to the identified frequencies and mode shapes, responses of the structure can be calculated. It is then possible to analyze load paths, deflections and stressing. Modal response analysis will also involve the combination of modes, using any of the common methods, direct sum, absolute sum, square root sum of squares (SRSS) and Complete Quadratic Combination (CQC).

Time domain analysis or time history analysis is used where frequency domain analysis is inappropriate, or where a more detailed answer is required. For example, time domain solutions are more appropriate for the analysis of varying damping, non-linear structural responses and where differential effects are important, such as displacement. Time domain analysis can be performed by direct integration, using implicit or explicit integration schemes, or by mode superposition. Mode superposition analysis will usually use the results of a mode extraction as the underlying basis for the time domain solution. Direct integration solutions are well suited to problems where damping variation, either throughout the structure or varying by response, occurs and where non-linear effects are likely to predominate. Time domain results can be used to generate input for sub-structure analysis, either using further time domain models or by generating "in structure" response spectra for modal response analysis. We use state-of-the-art software for complicated applications that involve complex geometry, behaviour, non-linearity, gap/contact etc. We provide in-depth theoretical and practical expertise in seismic analysis frequency and time domains.

### Sample Projects

La Joie Intake Tower Seismic upgrade