Browsing by Author "Kularathna, HGSR"

Now showing 1 - 5 of 5

item: Article-Abstract
An Approach to seismic analysis of (Engineered) Buildings in Sri Lanka
Lewangamage, CS; Kularathna, HGSR
Even though, Sri Lanka was believed to have no seismic threats, it is now realized that Sri Lanka can no longer be considered as a country safe from seismic threats following the recent events that occurred in and around the island. The present study is therefore aimed at providing guidance on suitable analysis procedure for buildings in Sri Lanka where the seismic consideration is explicitly warranted for a structure. The proposed guidelines in this study are based on Euro Code 8 (EN 1998-1: 2004): “Design of Structures for Earthquake Resistance”. Euro Code 8 was selected for this purpose as it allows national choices in defining seismic characteristics such as peak ground accelerations, response spectra, etc. in seismic design procedure. This study mainly focuses on these national choices and suitable values are proposed and discussed, depending on the available seismic data in Sri Lanka. Whenever there is a lack of data, suitable approaches are suggested comparing similar seismic codes such as IS 1893-1: 2002 and AS 1170.4: 2007. Finally, two case studies are carried out in order to illustrate how the developed guidelines can be used in the seismic design procedure of buildings particularly in Sri Lanka.
item: Conference-Abstract
Development of national guidelines for seismic analysis and design of (engineered) buildings in Sri Lanka
Kularathna, HGSR; Lewangamage, SR; Jayasinghe, MTR
Sri Lanka was believed to have no seismic threat compared to other natural disasters such as landslides, floods, droughts, etc. However, it has now been realized that Sri Lanka can no longer be considered as isolated from seismic threat following recent past events occurred in and around island. The only available document for the purpose of seismic design of buildings in Sri Lanka “Earthquake resistant detailing for buildings in Sri Lanka” published by the Society of Structural Engineers, Sri Lanka. The present study is therefore aimed to provide advice on the seismic design in Sri Lanka and provide guidance on suitable analyse seismic consideration is explicitly warranted for a structure. The proposed guidelines in this study are based on Euro Code 8 (EN 1998 Code 8 was selected for this purpose because it allows national choices in defining seismic characteristics such as peak ground accelerations, response spectra etc. in the seismic design procedure. It also allows national choices in selecting analysis and design resist seismic events. Therefore, this study mainly focuses on these national choices and suitable values are proposed and discussed depending on the available limited seismic data in Sri Lanka. Whenever there is no enough data, such as IS 1893-1: 2002 and AS 1170.4: 2007. Finally, two case studies are carried out in order to illustrate how the developed guidelines are used in the seismic design procedure of buildings specifically in Sri Lanka. The two buildings selected for this purpose represent buildings with high consequences of failure during an earthquake so that it clearly shows the significance of seismic consideration in the design procedure of buildings.
item: Thesis-Abstract
Development of National guidelines for seismic analysis and design of (Engineered) buildings in Sri Lanka
(2015-02-08) Kularathna, HGSR; Lewangamage, CS; Jayasinghe, MTR
Sri Lanka was believed to have no seismic threat compared to other natural disasters such as landslides, floods, droughts which often cause widespread devastations. However, it has now been realized that Sri Lanka can no longer be considered as isolated from seismic threat following recent past events occurred in and around island. Designers of structures in Sri Lanka often used to avoid seismic consideration in the design procedure essentially of buildings as Sri Lanka is located within the Indo-Australian plate and thus, the chances of inter-plate type earthquakes which take place at the plate boundaries causing significant damages are remote. However, it is possible to take place intra-plate type earthquakes at any place within the tectonic plate. A notable example of a damaging intra-plate earthquake is the devastating Gujarat Earthquake in 2001. The only available document for the purpose of seismic design of buildings in Sri Lanka is “Earthquake resistant detailing for buildings in Sri Lanka” published by the Society of Structural Engineers, Sri Lanka. The present study is therefore aimed to provide advice on how all of these factors would affect the need for seismic design in Sri Lanka and provide guidance on suitable analysis and design procedures for buildings when the seismic consideration is explicitly warranted for a structure. The proposed guidelines in this study are based on Euro Code 8 (EN 1998-1: 2004): “Design of Structures for Earthquake Resistance”. Euro Code 8 was selected for this purpose because it allows national choices in defining seismic characteristics such as peak ground accelerations, response spectra etc. in the seismic design procedure. It also allows national choices in selecting analysis and design procedures of buildings to resist seismic events. Therefore, this study mainly focuses on these national choices and suitable values are proposed and discussed depending on the available limited seismic data in Sri Lanka. Whenever there is no enough data, suitable approaches are given comparing similar seismic codes such as IS 1893-1: 2002 and AS 1170.4: 2007. Finally, two case studies are carried out in order to present how the developed guidelines are used in the seismic design procedure of buildings specifically in Sri Lanka. The two buildings selected for this purpose represent buildings with high consequences of failure during an earthquake so that it clearly shows the significance of seismic consideration in the design procedure of buildings.
item: Conference-Full-text
Structural assessment and rehabilitation option for Yudaganawa dagoba in Buttala
(2013-11-12) Kularathna, HGSR; Siriwardhana, DNTM; Sudharshana, WN; Lewangamage, CS
Yudaganawa dagoba in uva province is one of the largest stupes in Sri Lanka which dates back to 2nd century BC. Presently, this colossal stupa with a diameter about 91.2 m and reaching a height of 13 m is undergoing several issues which necessitate it to be rehabilitated. The stupa was found in ruins and grown with vegetation until it has been preserved by subsequent restoration efforts in the recent past. However, it is not standing at its original height well-matched with the circumference at its base. Further, existing formation of the structure, existing foundation and ground condition are unknown. This paper presents structural assessment of existing stupa and proposal for rehabilitation in order to build the stupa to its full height. A literature survey has been carried out to investigate the structural formation of stupas in ancient Sri Lanka. The geometry of the present stupa and the soil profile under the stupa were assessed. Material properties have been found with adequate laboratory testing. Present condition was modelled using finite element analysis employing SAP 2000 and PLAXIS 2D. The results show that the stresses generated within the existing stupa due to its self weight is well below than the compressive strength and the tensile strength of bricks. Based on the results, several alternative methods are proposed for rehabilitation and the options are analysed with respect to structural performance along with the existing condition and the religious beliefs, attitudes and rituals concerning the stupas. The possibility of cracking in the masonry due to the self weight in each alternative method was checked using a failure criteria developed based on the modified Von Mises theory. The final option was selected so as the stresses generated in the existing brickwork are satisfying the failure criteria and has the minimum intervention to the stupa in the context of ancient value and the concerns related to stupas. Consistent with that, it is shown; the existing stupa is capable of taking the load of proposed solid brick superstructure without showing any possibility of cracking.
item: Conference-Abstract
Structural assessment and rehabilitation option for Yudaganawa dagoba in Buttala
(2011) Kularathna, HGSR; Siriwardhana, DNTM; Sudharshana, WN; Lewangamage, CS
Yudaganawa dagoba in Uva province is one of the largest stupas in Sri Lanka which dates back to 2nd century BC. Presently, this colossal stupa with a diameter about 91.2 m and reaching a height of 13 m is undergoing several issues which necessitate it to be rehabilitated. The stupa was found in ruins and grown with vegetation until it has been preserved by subsequent restoration efforts in the recent past. However, it is not standing at its original height wellmatched with the circumference at its base. Further, existing formation of the structure, existing foundation and ground condition are unknown. This paper presents structural assessment of existing stupa and proposal for rehabilitation in order to build the stupa to its full height. A literature survey has been carried out to investigate the structural formation of stupas in ancient Sri Lanka. The geometry of the present stupa and the soil profile under the stupa were assessed. Material properties have been found with adequate laboratory testing. Present condition was modelled using finite element analysis employing SAP 2000 and PLAXIS 2D. The results show that the stresses generated within the existing stupa due to its self weight is well below than the compressive strength and the tensile strength of bricks. Based on the results, several alternative methods are proposed for rehabilitation and the options are analysed with respect to structural performance along with the existing condition and the religious beliefs, attitudes and rituals concerning the stupas. The possibility of cracking in the masonry due to the self weight in each alternative method was checked using a failure criteria developed based on the modified Von Mises theory. The final option was selected so as the stresses generated in the existing brickwork are satisfying the failure criteria and has the minimum intervention to the stupa in the context of ancient value and the concerns related to stupas. Consistent with that, it is shown; the existing stupa is capable of taking the load ofproposed solid brick superstructure without showing any possibility of cracking.