i8 | serviceability design of floor structures Figure 3 Partial floor configuration for the Shared Lab Building Case study Vibration control was a major design issue for the Shared Lab Building project in Salahaddin University, Erbil, Iraq. The Shared Lab is a six-story building including a penthouse level. It rests on partial basements and has an approximate built-up area of 60,000 m2, as shown on the previous page in Figure 2. To ensure a cost-effective solution, high sensitive equipment below 6 μm/s such as the nuclear magnetic resonance (NMR) was allocated at grade level at early stage of the design. A partial floor architectural configuration for the Shared Lab Building is shown in Figure 3. A finite element model is created for the 330 mm concrete slab floor system with drop panels using a column grid of 6.4 m x 9.6 m. The design superimposed dead load is taken as 0.45 t/m2 and the live load at 0.6 t/m2. The resulting natural frequency of the structure was found to be 4 Hz, which means that the floor had a low frequency, and its response was likely to be dominated by harmonic excitation. An 84-kg person is considered using a slow pace walking path inside the laboratory since it is a confined space (50 steps/min) as shown in Figure 4, and two fast pace walking paths in the corridor areas (100 steps/min) as shown in Figure 5. A time history analysis was undertaken on the structure to determine its vibration performance using a train of footfall force pulses as shown in Figure 6. Figure 4 Floor configurations - slow walking pace Figure 5 Floor configurations - fast walking pace Figure 6 Train of footfall force pulse in continuous walking 42