Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO

Transcription

1 ICCBT2008 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO M. I. Adiyanto*, Universiti Sains Malaysia, MALAYSIA T. A. Majid, Universiti Sains Malaysia, MALAYSIA S. S. Zaini, Universiti Sains Malaysia, MALAYSIA ABSTRACT Before the disaster of the century known as The Terrible Tsunami caused by heavy Sumatra Andaman earthquake in December 2004, it can be said that no one in Malaysia care about earthquake. Majority of Malaysian citizen does not worry to earthquake hazard. However, after experienced several tremors in Sabah and Peninsular Malaysia due to earthquakes occurred in Philippines and Indonesia, the question about ability of buildings in Malaysia to withstand the tremors are rising up. This issue has become serious when several earthquakes had occurred in Bukit Tinggi, Pahang in Since hospital is the most important place during disaster to give humanitarian aid and medical treatment, it is important to make sure that the hospital building can withstand the earthquake. The objective of this study is to make comparisons of analysis and design of a 3-storey hospital building. Several cases of s had been applied to the building separately to represent the different intensity of earthquake between Malaysia and Indonesia. The results of analysis show that the same building can withstand any intensity of earthquake. It mean that the building are suitable to be built in any area located near the epicenter such as Indonesia, or at a distant from the epicenter like Malaysia. The comparison of design due to all cases showed that the design for building located near the epicenter need more steel reinforcement to resist the bending moment. Keywords: 3 Storey Hospital, Seismic Loads, STAADPRo Software. *Correspondence Author: Mr. Mohd Irwan Adiyanto, Universiti Sains, Malaysia. Tel: , Fax: irwano_07@yahoo.com ICCBT C - (35) - pp

2 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. 1 INTRODUCTION Before the year of 2004, nobody concern about earthquake in Malaysia. This is because Malaysia was lucky to be located outside the earthquake region and logically, it will be no hazards for Malaysian due to the earthquake. However, after a great Asian Disaster of tsunami on 26 th December 2004 [1], followed by several earthquakes in 2005 until nowadays, the safety of buildings in Malaysia subjected to ing had become an issue. The government, local authorities, structural engineers, architects, and other related professionals now start to discuss about the relevant of building with consideration of in Malaysia. From 26 th December 2004 until nowadays, so many earthquakes had occurred in South East Asia especially in Indonesia and Philippines. The tsunami disaster on December 2004 [1] was followed by tremor in Nias Island, Indonesia in March 2005 [2]. Then, the earthquake also occurred in Jogjakarta in May 2006 before the disaster was come again in September 2007 in Bengkulu. However, the epicenter of earthquakes was located outside Peninsular Malaysia and the tremors not give any effect to buildings in Malaysia. But, a small scale of tremor then was occurred in Bukit Tinggi, Malaysia in December 2007 [3]. Thus, a panic situation was happened to the residents of Bukit Tinggi due to the unexpected disaster. On 28 th March 2005, a heavy earthquake at 8.7 Richter scale was occurred in Nias Island [2], Indonesia (Figure 1). The tremor also was felt at several places in Peninsular Malaysia especially Penang and Kuala Lumpur. Although that earthquake did not cause any Tsunami wave, the shocking tragedy had killed more than 1000 people and caused damage to many buildings in Gunung Sitoli, Nias. This also happened to the Gunung Sitoli General Hospital which was also functioned as operation center to give medical treatment to the victims. In this paper, the main focus is to analyze the bending moment, shear force, and inter-storey drift of 3-storey hospital building due to different intensity of using STAAD Pro. Then, to design a selected beam of 3-storey hospital building due to different intensity of based on American Concrete Institute [4]. Finally, this paper had done the comparison of design and detailing for the selected beam due to different intensity of. NORTH SUMATRA PENINSULAR MALAYSIA NIAS ISLAND Figure 1: Location of Nias Island (Google Earth) 378 ICCBT C - (35) - pp

3 M. I. Adiyanto et. al. 2. METHOD AND BASIC THEORY This paper contains several steps in order to achieve its objectives. The important steps are simplification of floor plan, modeling using STAAD Pro software with different input of intensity, analysis of bending moment, shear force, and inter-storey drift. Then, the design for a selected symmetrical beam had been done to compare the changes of steel reinforcement required and provided due to different intensity of. The dead s and live s are taken from BS6399:1997 [5] and will be determined by using UBC 1994 equivalent lateral force procedure [6]. 2.1 Determination of Seismic Load Intensity The determination of intensity is based on equivalent static force procedure in UBC 1994 [6]. Step 1: Determination of numerical coefficient, C: Step 2: Determination of total weight of the structure, W: C = 1.25 S / T 2/3 (1) W = n W X i= 1 (2) W x = W A W B W C W D W equip (3) Figure 2: Tributary weight for calculation (UBC94) Step 3: Determination of design base shear: V = [Z I C / R w ] W (4) ICCBT C - (35) - pp

4 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. Step 4: Distribution of lateral force: V = F t F i F n i= 1 ( V F ) i = t N w h i= 1 i w i i h i (5) (6) 2.2 Beam Design for Gravity Load The beam design for selected beam under consideration of gravity only is based on Clause in BS 8110: part 1:1997 [7]. Step 1: Area of steel reinforcement required: M K = (7) 2 f bd CU K Z = d (8) 0.9 M AS = (9) 0.95f Z Y Step 2: Checking for minimum and maximum reinforcement: 100A 0.13< S < 4.0 (10) bd 2.3 Beam Design for Seismic Load For case of combination between gravity and, the beam design is referred to special provisions for design as mentioned in chapter 21, American Concrete Institute [4]. The steps of flexural reinforcement design are following several equations as shown below: Step 1: Area of steel reinforcement required: A S Mu = (11) φ f j d Y Step 2: Moment capacity checking: 380 ICCBT C - (35) - pp

5 M. I. Adiyanto et. al. a A F = S Y (12) 0.85 f ' a φ M p = φ AS fy d (13) 2 Step 3: Checking for minimum and maximum reinforcement: C b W A 3 f ' 200b C W S Pr ovided > AS min = bw d, (14) fy fy d AS ρ = < (15) b d W 3. RESULT AND ANALYSIS In this paper, the observation about effect of different values of on bending moment has been done to a selected beam in z-direction. A three span beam labeled as member 575, 576, and 577 located at gridline F/1-F/6 has been chosen since the beam supports widest floor area among other beams in z-direction. So, the beam will support the highest distribution of dead and live compared to other beams in z-direction. Figure 3 shows the location of selected frame while Figure 4 shows the side elevation of selected frame. Figure 3: Location of selected frame in z-direction ICCBT C - (35) - pp

6 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. SEISMIC LOAD (Z-DIRECTION) Ground level m 3.5 m 3.5 m 5m 6m 5m Figure 4: Side elevation of selected frame 3.1 Effect on Bending Moment for a Selected Beam in Z-Direction Due to Different Values of Seismic Load 500 Bending moment (kn.m) Section of beam (m) Gravity Medium Low High Figure 5: Comparison of bending moment diagram for different intensity of Figure 5 shows the comparison of bending moment diagram for different intensity of applied to the structure. The comparison showed clearly that the values of bending moment caused by high intensity of are highest compared to other intensities. Table 1 below shows the comparison for the percentage of different for maximum bending moment due to different intensity of. The changing of maximum bending moment due to high applied compared to action of gravity only is very high up to 82.4 percent. The comparison of maximum moment then is presented graphically in Figure ICCBT C - (35) - pp

7 M. I. Adiyanto et. al. Table 1: Comparison of maximum bending moment value for selected beam under various intensity of in Z-direction Type of ing Maximum moment (kn.m) Percentage of different (%) Gravity Low Medium High Maximum bending moment (kn.m) Type of ing Gravity Low Medium High Figure 6: Comparison of maximum bending moment due to various type of ing. 3.2 Effect on Shear Force for a Selected Beam in Z-Direction Due to Different Values of Seismic Load 300 Shear force (kn) Section of beam (m) Gravity Low Medium High Figure 7: Shear force diagram for each type of ing ICCBT C - (35) - pp

8 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. Figure 7 shows the comparison of shear force diagram for different intensity of applied to the structure. The comparison showed clearly that the values of shear force caused by high intensity of are highest compared to other intensities. Table 2 below shows the comparison for the percentage of different for maximum shear force due to different intensity of. The changing of maximum shear force due to high applied compared to action of gravity only is high up to 13.2 percent. The comparison of maximum shear then is presented graphically in Figure 8. Table 2: Comparison of maximum shear force value for selected beam under various intensity of in Z-direction Type of ing Maximum shear (kn) Percentage of different (%) Gravity Low Medium High Maximum shear force (kn) Type of ing Gravity Low Medium High Figure 8: Comparison of maximum shear force due to various type of ing. 3.3 Inter-storey Drift Index Checking Inter-storey drift is the lateral displacement of one level of a multi-storey structure relative to the lower level. According to Smith and Coull [8], the inter-storey drift index can be defined as: Inter-storey drift index = maximum deflection at a particular storey (16) Storey height In accordance with UBC 1997 code, for the building with fundamental period, T is less than 0.7 seconds, the inelastic drift are limited to a maximum times the storey height. For a building with natural periods 0.7 seconds or greater, the limitation for inter-storey drift is 384 ICCBT C - (35) - pp

9 M. I. Adiyanto et. al times the storey height. Since the value of period, T in this study was 0.43 second, the limitation for inter-storey drift is 8.75 cm. Table 3: Inter-storey drift in x-direction at particular storey under various values Inter-storey drift at particular storey (cm) Level Gravity Low (xdirection) 1.0ELZ Medium (xdirection) 1.0ELZ High (xdirection) 1.0ELZ Inter-storey drift limit, h/40 (cm) Table 4: Inter-storey drift in z-direction at particular storey under various values Inter-storey drift at particular storey (cm) Level Gravity Low (zdirection) 1.0ELZ Medium (zdirection) 1.0ELZ High (zdirection) 1.0ELZ Inter-storey drift limit, h/40 (cm) Table 3 and Table 4 represent the result for inter-storey drift at particular level in x-direction and z-direction respectively. For both table, the inter-storey drift at particular level due to action of different type of ing are not exceeding the inter-storey drift limit. This result mean that the horizontal movement of columns joint are below the limitation and acceptable for design purposes even for high. From Table 3 and Table 4, it can be observed that the inter-storey drift for each level are different due to type of ing applied. At the same level, the value of inter-storey drift is ICCBT C - (35) - pp

10 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. increase start from gravity, low, medium, and followed by the high. Since maximum displacement of each level cause by the action of high to the building, it is now the same result for inter-storey drift. Maximum value of inter-storey drift in x and z-direction is cm and 4.72 cm respectively. The maximum inter-storey drift was occurred at first level for all cases of and for both x and z direction. The inter-storey drift then decreased until the top level. So, the lateral displacement for both x and z direction at the roof level are smaller relative to the third level of the building. This is due to smaller value of act on roof joint compared to the lower joints for all cases of. 3.4 Comparison of a Beam Design Due to Different Type of Loading Applied. As well as the analysis for bending moment, the comparison on beam design also using the same beam. Hence, the value of bending moment as discussed before is used for design purposes. In this study, the comparison of beam design are based on three different section that are the exterior support, middle span, and interior support of the beam. The location of exterior support, middle span, and interior support are shown in Figure m 6m 5m Exterior support Middle span Interior support Figure 9: Location of exterior support, middle span, and interior support The comparison of beam design in term of size of section and bending reinforcement are tabulated in Table 5. From that table, it can be observed clearly that the area of steel reinforcement required is increase directly with the value of maximum moment for exterior support, middle span, and interior support. The cross section area of steel required for high is the highest among all cases. 386 ICCBT C - (35) - pp

11 M. I. Adiyanto et. al. From Table 5, the flexural reinforcements provided for interior support are highest compared to flexural reinforcement provided for exterior support and middle span of the beam. This is due to the value of bending moment are highest at interior support compared to other section for all cases of ing. However, the section of beam is remaining same for all cases by using 200 mm for width and 600 mm for height. The cross section areas of steel reinforcements provided are higher than required. Table 5: Comparison of beam design due to different type of ing applied Section Design parameter Gravity Low Medium High Exterior support (top reinf) Middle span (bottom reinf) Interior support (top reinf) Size of section (mm 2 ) 200 x x x x 600 Maximum moment (kn.m) Bending reinforcement 2Y12 2Y20 3Y20 4Y25 As required (mm 2 ) As provided (mm 2 ) Size of section (mm 2 ) 200 x x x x 600 Maximum moment (kn.m) Bending reinforcement 4Y16 4Y16 4Y16 3Y20 As required (mm 2 ) As provided (mm 2 ) Size of section (mm 2 ) 200 x x x x 600 Maximum moment (kn.m) Bending reinforcement 4Y20 4Y20 3Y25 3Y25 2Y20 As required (mm 2 ) As provided (mm 2 ) CONCLUSION In this paper, it is observed that the values of in this study are higher where the coefficient for importance factor was taken as 1.25 for hospital building. So, the value of shear base, V is higher than residential buildings by 20 percent. Since the height of that hospital is just 10.5 meter, so the time period of ing, T is short and less than 7.0 second. Thus, the value of F t is equal to zero. In this case, F t was not applied at the top of the building. So, s act on roof level was less than the lower level. The value of bending moment at any reference points at the beam is differ due to different type of ing applied to the beam and joint. From the analysis, the value of bending ICCBT C - (35) - pp

12 Analysis and Design of 3 Storey Hospital Structure Subjected To Seismic Load Using STAAD PRO. moment at all supports are increase from gravity to low, medium, and high applied. For bending moment at each middle span of the beam, no dramatic change occurred due to different type of ing applied. However, no dramatic change for bending moment at any section of the beam due to low applied compared to gravity only. From the analysis of shear force, it had been observed that the value of shear force in any reference points at the beam is differ due to different type of ing applied to the beam and joint. From the analysis, the value of shear forces at all supports are increase from gravity to low, medium, and high applied. In can be concluded that higher will produce higher bending moment and shear force. In term of inter-storey drift checking, the inter-storey drift limit for both x and z direction is 8.75 cm. At the same level, the value of inter-storey drift is increase start from gravity, low, medium, and followed by the high. Maximum value of inter-storey drift in x and z-direction is cm and 4.72 cm respectively. Since the limit of inter-storey drift was not exceeded for all cases of ing, hence the low rise hospital building can withstand any type of. The beam design for all cases of ing are satisfy with 200 mm x 600 mm rectangular section. However, the cross sectional area of steel reinforcement required for bending are differ due to different type of ing. High requires the highest cross sectional area of steel reinforcement compared to other s. Hence, the material costs to build the building near the epicenter are higher than in a distant location from epicenter. Acknowledgements The authors would like to thanks the School of Civil Engineering, Universiti Sains Malaysia (USM). REFERENCES [1]. Tsunami, 2004 Indian Ocean Earthquake, available from: [2]. Nias Earthquake, 2005 Sumatra Earthquake, available from: [3]. Malaysian Meteorological Services, Ministry of Science technology and Innovation, available from: [4]. American Concrete Institute: Building code requirements for structural concrete (ACI ) and commentary (ACI 318R-05). [5]. BS 6399: Part 1:1996: Loading for building, Part 1, Code of practice for dead and imposed. [6] Uniform Building Code, Equivalent Lateral Force Procedure (Static Method) [7] BS 8110: Part 1: Structural use of concrete, Part 1. Code of practice for design and construction. [8] Smith, B.S. and Coull, A. (1991). Tall Building Structures: Analysis and Design, John Wiley & Sons, INC, Canada. 388 ICCBT C - (35) - pp