CONSTRUCŢII – No. 2 / 2012 16 ASSESSMENT OF THE MATERIAL PROPERTIES OF A FIRE DAMAGED BUILDING Oladipupo OLOMO 1, Olufikayo ADERINLEWO 2 , Moses TANIMOLA 3 , Silvana CROOPE 4 1,2,3 Department of Civil Engineering, Federal University of Technology Akure, E-mail: faderin2010@yahoo.com 4 Delaware Department of Transportation, Delaware, USA, E-mail: silcroope@gmail.com ABSTRACT This study identifies a process for assessing the material properties of a fire damaged building so as to determine whether the remains can be utilized in construction or be demolished. Physical and chemical analysis were carried out on concrete and steel samples taken from various elements of the building after thorough visual inspection of the entire building had been conducted. The physical (non-destructive) tests included the Schmidt hammer and ultrasonic pulse velocity tests on the concrete samples, tensile strength test on the steel samples and chemical tests involving the assessment of the quantities of cement, sulphates and chloride concentrations in the samples. A redesign of the building elements was also carried out and the results were compared with the existing design. The non-destructive test results indicated compressive strengths as low as 9.9 N/mm 2 , the tensile strength test indicated a maximum strength of 397.48 N/mm 2 and the chemical test indicated chloride contents as high as 0.534 g per gramme of concrete. These properties deviated significantly from standard requirements. Based on these results, it was concluded that the remains of the building should be demolished. Keywords: ultrasonic pulse velocity; tensile strength; compressive strength; non-destructive tests REZUMAT Studiul de faţă identifică un proces de evaluare a proprietăţilor materialelor unei clădiri avariate de cutremur, astfel încât să se determine dacă părţile rămase pot fi utilizate în construcţie sau dacă trebuie realizată demolarea. Au fost realizate analize fizice şi chimice asupra unor probe de beton şi oţel prelevate din diferite elemente ale clădirii, după o atentă inspecţie vizuală a întregii clădiri. Încercările fizice (ne-distructive) au inclus încercarea cu sclerometrul Schmidt şi cu metoda ultrasonică de impuls pe probe de beton, încercarea de rezistenţă la întindere pe probe de oţel, ca şi probe chimice, implicând evaluarea cantităţilor de ciment, sulfaţi şi a concentraţiilor de cloruri din probe. De asemenea, a fost efectuată o reproiectare a elementelor de construcţie, iar rezultatele au fost comparate cu proiectul iniţial. Rezultatele testelor nedistructive au indicat rezistenţe la compresiune scăzute până la 9.9 N/mm 2 , încercarea de rezistenţă la întindere a indicat o rezistenţă maximă de 397.48 N/mm 2 , iar testul chimic a indicat un conţinut de cloruri de până la 0.534 g pe gram de beton. Aceste proprietăţi deviază semnificativ de la cerinţele standardelor. Pe baza acestor rezultate, s-a tras concluzia că părţile de clădire rămase ar trebui demolate. Cuvinte cheie: viteza pulsului ultrasonic, rezistenţă la întindere, rezistenţă la compresiune, încercări nedistructive 1. 1. INTRODUCTION A building is essentially a space protected from the natural environment and which is constructed for a specific purpose. The structural elements are parts of the building that cannot be conceived in isolation but are part of the whole design. A structural element (such as a beam, column, slab) carries the load on it by a system of bending moments, shear forces and axial forces acting in one, two or three directions depending on the nature of the structural elements. These elements fail due to several reasons such as inadequate design, poor workmanship, overloading and fire occurrence. The failure of the building elements usually occurs over a certain period of time called the design life and this may not be noticed if adequately maintained but when a fire disaster occurs there is an outright change. The fire hastens the reactions by exposing the structural elements to environmental