STRUCTURAL DEFORMATION SURVEY A CASE STUDY OF OBASANJO LIBRARY COMPLEX THE FEDERAL POLYTECHNIC DAMATURU YOBE STATE, NIGERIA

The subsidence survey being one for accurate measurement of the movement of building or structure in order to undertake a visual inspection with the aim of assessing the extent and seriousness of the movement and damage of the structure (J.F.A 1992). This become necessary considering how the structure (Obasanjo library complex) is gradually changing and experiencing cracks hence the need to monitor the structure. The periodic monitoring combined both conventional survey (trigonometric heightening) and satellite (global positioning system) where level, electronic theodolite as well as global navigation satellite system receiver was used to determine the external movement of the structure, the acquired data was processed the result revealed that the average height observed of the North, South and East of the building (study area) is relatively same because the most probable value, standard deviation and standard error are almost the same as 9.052, 0.00821 and 0.0055 respectively. Only in the case of Western part that is a little bit different as the most provable value (MPV), standard deviation (SD) and standard error (SE) are 9.0384, 0.02232 and 0.0082 which indicate a little sink of 0.014m height, 0.014m MPV and 0.0027m standard error. However, at a fitted trend equation of Yt = 9.0477- 000031xt. The trend analysis plot revealed that the variables such as Actual, Fits and Forcast has an average accuracy of 0.0074075 mean absolute percentage error (MAPE), 0.0006704 Mean absolute deviation (MAD) and 0.000012 Mean square deviation (MSD).