The pedestrian bridge is very flexible as well as slender structure. Whereas the natural frequency are like these structure which is in the range of the dynamic excitation of frequency caused by the running or walking. Therefore bridge could easily simulated and vibrate the pedestrian walks to run across the bridge. The fundamental natural frequency f_v of a bridge in the vertical direction is defined as below;

〖F_(p.v) (t)=180.sin⁡(2.π.f〗_v.t),N

Natural frequency in vertical direction shall be greater than 5 Hz to avoid any issues associated with the first as well as second walking harmonic. The method for determination of frequencies of single-span beams is given below;

f_i= α_i/2π √((E.I)/(ml^4 )),Hz

Whereas in f_i is the i^th natural frequency;

Fundamental natural frequencies in vertical plus horizontal direction simplified method presented by above equation. Range of normal walking frequencies is 1.6 Hz to 2.4 Hz, a second harmonic of these footstep rates might match with the fundamental natural frequency of the bridge in the vertical direction (4.02 Hz) and cause a resonant response (Gheitasia & al, 2016).

Now by using Finite Element method; the MATALB code of the natural frequency for the merchant bridge design is given below;

MATALB Code of The experimental results

Result of The experimental

2. Measure the acceleration response with:

a. A person walking slowly across the bridge

Matlab code of The experimental results

Result

b. A person walking quickly across the bridge

MATLAB result

c. A person jogging across the bridge

Matlab Code

Result

6. Uncertainty analysis of the data

Results

References of The experimental results

Gheitasia, A., & al, e. (2016). Experimental and analytical vibration serviceability assessment of an in-service footbridge. Case Studies in Nondestructive Testing and Evaluation, 6, 79–88.

Grandić, I. Š. (2015). SERVICEABILITY VERIFICATION OF PEDESTRIAN BRIDGES UNDER PEDESTRIAN. Tehnički vjesnik, 22(2), 527-537.