EXPERIMENTAL STUDIES ON 1/5 SCALED REINFORCED CONCRETE FRAMES BY USING DIFFERENT STRENGTHENED METHODS
Year 2019,
Volume: 7 Issue: 3, 663 - 680, 01.09.2019
Fatih Süleyman Balık
Fatih Bahadır
Abstract
In this experimental study; five RC frames with a scale of 1/5, single
spans and two storey were produced so as to reflect the characteristics of
existing structures. Two RC frames were used as the reference specimens that
without an infill wall and autoclaved aerated concrete blocks (AAC) infilled
wall. Three of these RC frames were strengthened as CFS (Cold Formed Steel) drywall
system, infill RC shear wall and both external RC shear wall and column
jacketing. All specimens produced were tested under reverse cyclic lateral
loading and constant vertical loading. Strength, stiffness and energy
dissipation capacities of all test specimens are compared with each other. The
lateral load carrying capacity and energy dissipation capacities of
strengthened specimens have occurred higher than reference specimens. But
initial stiffness and stiffness at the max lateral load of specimen
strengthened with CFS drywall system have occurred lower than reference
specimen with AACW.
Supporting Institution
Necmettin Erbakan University Scientific Research Projects Office (BAP)
Thanks
The project presented in this article was supported by Necmettin Erbakan University Scientific Research Projects Office (BAP).
References
- Accorti, M., Baldassino, N., Zandonini, R., Scavazza, F., Rogers, C. A., 2016, “Reprint of Response of CFS Sheathed Shear Walls”, Structures, Vol. 8, pp. 318-330.
- Akin, E., Korkmaz, S. Z., Korkmaz, H. H., Diri, E., 2016, “Rehabilitation of Infilled Reinforced Concrete Frames with Thin Steel Plate Shear Walls”, Journal of Performance of Constructed Facilities, Vol. 30, No. 4, 04015098.
- Altin, S., Anil, O., Kara, M.E., 2008, “Strengthening of RC Nonductile Frames with RC Infills: An Experimental Study”, Cement&Concrete Composites, Vol. 30, No. 7, pp. 612-621.
- Altın, S., Ersoy, U., Tankut, T., 1992, “Hysteretic Response of Reinforced Concrete Infilled Frames”, ASCE, Journal of Structural Engineering, Vol. 118, No. 8, pp. 2133-2150.
- Anıl, Ö., Altın, S., 2007, “Experimental Study on Reinforced Concrete Partially Infilled Frames”, Engineering Structures, Vol. 29, No. 3, pp. 449-460.
- Aykaç, B., Özbek, E., Babayani, R., Baran, M., Aykaç, S., 2017, “Seismic Strengthening of Infill Walls with Perforated Steel Plates”, Engineering Structures, Vol. 152, pp. 168-179.
- Bahadır, F., Balık, F.S., 2017, “Predicting Displacement Data of Three-Dimensional Reinforced Concrete Frames with Different Strengthening Applications Using ANN”, Periodica Polytechnica Civil Engineering, Vol. 61, No. 4, pp. 843-856.
- Balık, F.S., Bahadır, F., Kamanlı, M., Korkmaz, H.H., Ünal, A., Kaltakcı, M.Y., 2018, “The Behavior of Strengthening 1/3 Scaled Reinforced Concrete Frames by Using Reinforced Concrete Shear Walls with Openings”, Selcuk Univ. J. Eng. Sci. Tech., Vol. 6, No. 2, pp. 279-295.
- Baran, E., Alica, Cagatay., 2012, "Behavior of cold-formed steel wall panels under monotonic horizontal loading", Journal of Constructional Steel Research, Vol. 79, pp. 1-8.
- Baran, M., Susoy, M., Tankut, T., 2011, “Strengthening of Deficient RC Frames with High Strength Concrete Panels: An Experimental Study”, Structural Engineering and Mechanics, Vol. 37, No. 2, pp. 177-196.
- Baran, M., Tankut T., 2011, “Experimental Study on Seismic Strengthening of Reinforced Concrete Frames by Precast Concrete Panels”, ACI Struct. J., Vol. 108,I No. 2, pp. 227-237.
- Baran, M., 2005, Precast Concrete Panel Reinforced Infill Walls for Seismic Strengthening of Reinforced Concrete Framed Structures, Ph.D. Thesis in Civil Engineering, Middle East Technical University, Ankara.
- Buonopane, S.G., White, R.N., 1999, “Pseudodynamic Testing of Masonry Infilled Reinforced Concrete Frames”, ASCE, J of Structural Engineering, Vol. 125, No. 6, pp. 578- 589.
- Carrillo, J., Alcocer, S.M., 2013, “Experimental Investigation on Dynamic and Quasi‐Static Behavior of Low‐Rise Reinforced Concrete Walls”, Earthquake Engineering & Structural Dynamics, Vol. 42, No. 5, pp. 635-652.
- Choi, I.R., Park, H.G., 2010, “Cyclic Loading Test for Reinforced Concrete Frame with Thin Steel Infill Plate”, Journal of Structural Engineering, Vol. 137, No. 6, pp. 654-664.
- Dautaj, A.D., Kadiri, Q., Kabashi, N., 2018, “Experimental Study on The Contribution of Masonry Infill in The Behavior of RC Frame Under Seismic Loading”, Engineering Structures, Vol. 165, pp. 27-37.
- Demirel, I.O., Yakut, A., Binici, B., Canbay, E., “Betonarme Çerçevelerde Dolgu Duvar Etkisinin İncelenmesi Üzerine Deneysel Çalışma”, 3. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, DEÜ–İzmir, 14-16 Ekim 2015.
- Demirel, I.O., Canbay, E., Binici, B., Yakut, A., Eryurtlu, Z., “Gazbeton Dolgulu Betonarme Çerçevelerin Deprem Performansı Üzerine Deneysel Çalışma”, 3. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, DEÜ–İzmir, 14-16 Ekim 2015.
- Elgaaly, M., 1998, “Thin Steel Plate Shear Walls Behavior and Analysis”, Thin-Walled Structures, Vol. 32, No. 1-3, pp. 151-180.
- Erdem I, Akyüz U., Ersoy, U., Özcebe, G., 2006, “An Experimental Study on Two Different Strengthening Techniques for RC Frames”, Engineering Structures, Vol. 28, No. 13, pp. 1843-1851.
- Fülöp, L.A., Dubina, D., 2004, "Performance of Wall-Stud Cold-Formed Shear Panels Under Monotonic and Cyclic Loading: Part I: Experimental Research", Thin-Walled Structures, Vol. 42, No. 2, pp. 321-338.
- Ha, S.K., Yu, S.Y., Kim, J.S., 2018, “Experimental Study on Existing Reinforced Concrete Frames Strengthened by L-type Precast Concrete Wall Panels to Earthquake-Proof Buildings”, KSCE Journal of Civil Engineering, Vol. 22, No. 9, pp. 3579-3591.
- Hayashi, T., Niwa, H., Fukuhara, M., "Strengthening Methods of The Existing Reinforced Concrete Buildings", Proceedings of The 7th World Conference on Earthquake Engineering, Istanbul-Turkey, 89-96, 8-13 September 1980.
- Higashi Y., Endo, T., Ohkubo, M., Shimizu, Y., “Experimental Study on Strengthening Reinforced Concrete Structure by Adding Shear Wall”, Proceedings of The 7th World Conference on Earthquake Engineering, Istanbul-Turkey, 173-180, 8-13 September 1980.
- Kamanlı, M., Korkmaz, H. H., Balık, F. S., Bahadır, F., “Sünek Olmayan B/A Çerçevelerin, Çelik Çaprazlarla, B/A Dolgu Duvarlarla ve Çelik Levhalar İle Güçlendirilmesi”, 1. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, Ankara, 1-9, 11-14 Ekim 2011.
- Kara M.E., 2006, Strengthening of Non-Ductile Reinforced Concrete Frames by Reinforced Concrete Partial Infills, Ph.D. Thesis, Gazi University, Institute of Science and Technology, Ankara.
- Kara, M.E., Altin, S., 2006, “Behavior of Reinforced Concrete Frames with Reinforced Concrete Partial Infills”, ACI Structural Journal, Vol.103, No. 5, pp. 701-709.
- Kaya, F., Tekeli, H., Anil, Ö., 2018, “Experimental Behavior of Strengthening of Masonry Infilled Reinforced Concrete Frames by Adding Rebar‐Reinforced Stucco”, Structural Concrete, pp.1-14.
- Korkmaz, S.Z., Kamanli, M., Balik, F.S., Bahadir, F., Korkmaz, H.H., 2011, Seismic Performance Improvement of Nonductile RC Frames with User Friendly External Strengthening Applications”, International Journal of Arts & Sciences, Vol. 4, No. 19, pp. 349-359.
- Lee, H.S., Woo, S.W., 2002, "Effect of Masonry Infills on Seismic Performance of a 3‐Storey R/C Frame with Non‐Seismic Detailing", Earthquake Engineering & Structural Dynamics, Vol. 31, No. 2, pp. 353-378.
- Mehrabi, A.B., Shing, P.B., Schuller, M.P., Noland, J.L., 1996, “Experimental Evaluation of Masonry-Infilled RC Frames”, Journal of Structural engineering, Vol. 122, No. 3, pp. 228-237.
- Mohebbi, S., Mirghaderi, S.R., Farahbod, F., Sabbagh, A.B., Torabian, S., 2016, "Experiments on Seismic Behaviour of Steel Sheathed Cold-Formed Steel Shear Walls Cladded by Gypsum and Fiber Cement Boards." Thin-Walled Structures, Vol. 104, pp. 238-247.
- Ozcebe, G., Ersoy, U., Tankut, T., Erduran, E., Keskin, R.S.O., Mertol, H.C., 2003, “Strengthening of Brick-Infilled RC Frames with CFRP”, Department of Civil Engineering, Middle East Technical University, Ankara-Turkey.
- Ozcebe, G., Ersoy, U., Tankut, T., Ugurhan Akyuz, U., Erduran, E., “Rehabilitation of Existing Reinforced Concrete Structures Using CFRP Fabrics”, 13th World Conference on Earthquake Engineering, Vancouver, B.C., Canada, paper no. 1393, 1-6 August 2004.
- Pan, C.L., Shan, M.Y., 2011, “Monotonic Shear Tests of Cold-Formed Steel Wall Frames with Sheathing”, Thin-Walled Structures, Vol. 49, No. 2, pp. 363-370.
- Suzuki, T., Choi, H., Sanada, Y., Nakano, Y., Kazuto Matsukawa, Devjyoti Paul, Gülkan, P., Binici, B., 2017, “Experimental Evaluation of The In-Plane Behaviour of Masonry Wall Infilled RC Frames”, Bulletin of Earthquake Engineering, Vol. 15, No. 10, pp. 4245-4267.
- Tankut, T., Ersoy, U., Ozcebe, G., Baran, M., Kuyucu, D., 2005, “In Service Seismic Strengthening of RC Framed Structures”, Seismic Assessment and Rehabilitation of Existing Buildings, International Closing Workshop, NATO Project Sfp., Vol. 977231, Istanbul, Turkey
- Wang, X., Ye, J., 2015, “Reversed Cyclic Performance of Cold-Formed Steel Shear Walls with Reinforced end Studs”, Journal of Constructional Steel Research, Vol. 113, pp. 28-42.
- Ye, J., Wang, X., Jia, H., Zhao, M., 2015, "Cyclic Performance of Cold-Formed Steel Shear Walls Sheathed with Double-Layer Wallboards on Both Sides", Thin-Walled Structures, Vol. 92, pp. 146-159.
- Yılmaz, Ü., Arslan, M.H., Kaltakcı, M.Y., 2010, “Betonarme Dış Perde Duvarla Güçlendirilmiş Çerçevelerin Dayanım Parametrelerinin Deneysel ve Analitik Yöntemlerle İrdelenmesi”, TÜBAV Bilim Dergisi, Vol. 3, No. 1, pp. 11-12.
- Zovkic, J., Sigmund, V., Guljas, I., 2013, “Cyclic Testing of a Single Bay Reinforced Concrete Frames with Various Types of Masonry Infill”, Earthquake engineering & structural dynamics, Vol. 42, No. 8, pp. 1131-1149.
1/5 Ölçekli Betonarme Çerçevelere Farklı Güçlendirme Metotları Uygulanması Üzerine Deneysel Çalışmalar
Year 2019,
Volume: 7 Issue: 3, 663 - 680, 01.09.2019
Fatih Süleyman Balık
Fatih Bahadır
Abstract
Bu deneysel
çalışmada; mevcut yapıların özelliklerini yansıtacak şekilde 1/5 ölçekli, tek
açıklıklı ve iki katlı 5 adet betonarme çerçeve üretilmiştir. Bu çerçevelerden
2 adedi referans numune olarak biri boş çerçeve diğeri gazbeton dolgu duvarlı
olarak kullanılmıştır. Diğer üç adet betonarme çerçeve ise soğukta
şekillendirilmiş çelik (CFS) duvar sistemi, betonarme dolgu duvarlı ve hem
düzlem dışı betonarme duvarlı hem de betonarme kolon mantolu olarak
güçlendirilmiştir. Üretilen tüm numuneler tersinir-tekrarlanır yatay yük ve sabit
düşey yükleme altında test edilmiştir. Test numunelerine ait dayanım, rijitlik
ve enerji tüketme kapasiteleri birbirleri ile karşılaştırılmıştır.
Güçlendirilmiş numunelere ait yatay yük taşıma ve enerji tüketme kapasiteleri,
referans numunelere göre daha yüksektir. Fakat soğukta şekillendirilmiş çelik
(CFS) duvar sistemi ile güçlendirilen numunenin başlangıç ve maksimum yükteki
rijitlik değerleri, gazbeton dolgu duvarlı (AACW) referans numuneninkinden daha
düşük olmuştur.
References
- Accorti, M., Baldassino, N., Zandonini, R., Scavazza, F., Rogers, C. A., 2016, “Reprint of Response of CFS Sheathed Shear Walls”, Structures, Vol. 8, pp. 318-330.
- Akin, E., Korkmaz, S. Z., Korkmaz, H. H., Diri, E., 2016, “Rehabilitation of Infilled Reinforced Concrete Frames with Thin Steel Plate Shear Walls”, Journal of Performance of Constructed Facilities, Vol. 30, No. 4, 04015098.
- Altin, S., Anil, O., Kara, M.E., 2008, “Strengthening of RC Nonductile Frames with RC Infills: An Experimental Study”, Cement&Concrete Composites, Vol. 30, No. 7, pp. 612-621.
- Altın, S., Ersoy, U., Tankut, T., 1992, “Hysteretic Response of Reinforced Concrete Infilled Frames”, ASCE, Journal of Structural Engineering, Vol. 118, No. 8, pp. 2133-2150.
- Anıl, Ö., Altın, S., 2007, “Experimental Study on Reinforced Concrete Partially Infilled Frames”, Engineering Structures, Vol. 29, No. 3, pp. 449-460.
- Aykaç, B., Özbek, E., Babayani, R., Baran, M., Aykaç, S., 2017, “Seismic Strengthening of Infill Walls with Perforated Steel Plates”, Engineering Structures, Vol. 152, pp. 168-179.
- Bahadır, F., Balık, F.S., 2017, “Predicting Displacement Data of Three-Dimensional Reinforced Concrete Frames with Different Strengthening Applications Using ANN”, Periodica Polytechnica Civil Engineering, Vol. 61, No. 4, pp. 843-856.
- Balık, F.S., Bahadır, F., Kamanlı, M., Korkmaz, H.H., Ünal, A., Kaltakcı, M.Y., 2018, “The Behavior of Strengthening 1/3 Scaled Reinforced Concrete Frames by Using Reinforced Concrete Shear Walls with Openings”, Selcuk Univ. J. Eng. Sci. Tech., Vol. 6, No. 2, pp. 279-295.
- Baran, E., Alica, Cagatay., 2012, "Behavior of cold-formed steel wall panels under monotonic horizontal loading", Journal of Constructional Steel Research, Vol. 79, pp. 1-8.
- Baran, M., Susoy, M., Tankut, T., 2011, “Strengthening of Deficient RC Frames with High Strength Concrete Panels: An Experimental Study”, Structural Engineering and Mechanics, Vol. 37, No. 2, pp. 177-196.
- Baran, M., Tankut T., 2011, “Experimental Study on Seismic Strengthening of Reinforced Concrete Frames by Precast Concrete Panels”, ACI Struct. J., Vol. 108,I No. 2, pp. 227-237.
- Baran, M., 2005, Precast Concrete Panel Reinforced Infill Walls for Seismic Strengthening of Reinforced Concrete Framed Structures, Ph.D. Thesis in Civil Engineering, Middle East Technical University, Ankara.
- Buonopane, S.G., White, R.N., 1999, “Pseudodynamic Testing of Masonry Infilled Reinforced Concrete Frames”, ASCE, J of Structural Engineering, Vol. 125, No. 6, pp. 578- 589.
- Carrillo, J., Alcocer, S.M., 2013, “Experimental Investigation on Dynamic and Quasi‐Static Behavior of Low‐Rise Reinforced Concrete Walls”, Earthquake Engineering & Structural Dynamics, Vol. 42, No. 5, pp. 635-652.
- Choi, I.R., Park, H.G., 2010, “Cyclic Loading Test for Reinforced Concrete Frame with Thin Steel Infill Plate”, Journal of Structural Engineering, Vol. 137, No. 6, pp. 654-664.
- Dautaj, A.D., Kadiri, Q., Kabashi, N., 2018, “Experimental Study on The Contribution of Masonry Infill in The Behavior of RC Frame Under Seismic Loading”, Engineering Structures, Vol. 165, pp. 27-37.
- Demirel, I.O., Yakut, A., Binici, B., Canbay, E., “Betonarme Çerçevelerde Dolgu Duvar Etkisinin İncelenmesi Üzerine Deneysel Çalışma”, 3. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, DEÜ–İzmir, 14-16 Ekim 2015.
- Demirel, I.O., Canbay, E., Binici, B., Yakut, A., Eryurtlu, Z., “Gazbeton Dolgulu Betonarme Çerçevelerin Deprem Performansı Üzerine Deneysel Çalışma”, 3. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, DEÜ–İzmir, 14-16 Ekim 2015.
- Elgaaly, M., 1998, “Thin Steel Plate Shear Walls Behavior and Analysis”, Thin-Walled Structures, Vol. 32, No. 1-3, pp. 151-180.
- Erdem I, Akyüz U., Ersoy, U., Özcebe, G., 2006, “An Experimental Study on Two Different Strengthening Techniques for RC Frames”, Engineering Structures, Vol. 28, No. 13, pp. 1843-1851.
- Fülöp, L.A., Dubina, D., 2004, "Performance of Wall-Stud Cold-Formed Shear Panels Under Monotonic and Cyclic Loading: Part I: Experimental Research", Thin-Walled Structures, Vol. 42, No. 2, pp. 321-338.
- Ha, S.K., Yu, S.Y., Kim, J.S., 2018, “Experimental Study on Existing Reinforced Concrete Frames Strengthened by L-type Precast Concrete Wall Panels to Earthquake-Proof Buildings”, KSCE Journal of Civil Engineering, Vol. 22, No. 9, pp. 3579-3591.
- Hayashi, T., Niwa, H., Fukuhara, M., "Strengthening Methods of The Existing Reinforced Concrete Buildings", Proceedings of The 7th World Conference on Earthquake Engineering, Istanbul-Turkey, 89-96, 8-13 September 1980.
- Higashi Y., Endo, T., Ohkubo, M., Shimizu, Y., “Experimental Study on Strengthening Reinforced Concrete Structure by Adding Shear Wall”, Proceedings of The 7th World Conference on Earthquake Engineering, Istanbul-Turkey, 173-180, 8-13 September 1980.
- Kamanlı, M., Korkmaz, H. H., Balık, F. S., Bahadır, F., “Sünek Olmayan B/A Çerçevelerin, Çelik Çaprazlarla, B/A Dolgu Duvarlarla ve Çelik Levhalar İle Güçlendirilmesi”, 1. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, Ankara, 1-9, 11-14 Ekim 2011.
- Kara M.E., 2006, Strengthening of Non-Ductile Reinforced Concrete Frames by Reinforced Concrete Partial Infills, Ph.D. Thesis, Gazi University, Institute of Science and Technology, Ankara.
- Kara, M.E., Altin, S., 2006, “Behavior of Reinforced Concrete Frames with Reinforced Concrete Partial Infills”, ACI Structural Journal, Vol.103, No. 5, pp. 701-709.
- Kaya, F., Tekeli, H., Anil, Ö., 2018, “Experimental Behavior of Strengthening of Masonry Infilled Reinforced Concrete Frames by Adding Rebar‐Reinforced Stucco”, Structural Concrete, pp.1-14.
- Korkmaz, S.Z., Kamanli, M., Balik, F.S., Bahadir, F., Korkmaz, H.H., 2011, Seismic Performance Improvement of Nonductile RC Frames with User Friendly External Strengthening Applications”, International Journal of Arts & Sciences, Vol. 4, No. 19, pp. 349-359.
- Lee, H.S., Woo, S.W., 2002, "Effect of Masonry Infills on Seismic Performance of a 3‐Storey R/C Frame with Non‐Seismic Detailing", Earthquake Engineering & Structural Dynamics, Vol. 31, No. 2, pp. 353-378.
- Mehrabi, A.B., Shing, P.B., Schuller, M.P., Noland, J.L., 1996, “Experimental Evaluation of Masonry-Infilled RC Frames”, Journal of Structural engineering, Vol. 122, No. 3, pp. 228-237.
- Mohebbi, S., Mirghaderi, S.R., Farahbod, F., Sabbagh, A.B., Torabian, S., 2016, "Experiments on Seismic Behaviour of Steel Sheathed Cold-Formed Steel Shear Walls Cladded by Gypsum and Fiber Cement Boards." Thin-Walled Structures, Vol. 104, pp. 238-247.
- Ozcebe, G., Ersoy, U., Tankut, T., Erduran, E., Keskin, R.S.O., Mertol, H.C., 2003, “Strengthening of Brick-Infilled RC Frames with CFRP”, Department of Civil Engineering, Middle East Technical University, Ankara-Turkey.
- Ozcebe, G., Ersoy, U., Tankut, T., Ugurhan Akyuz, U., Erduran, E., “Rehabilitation of Existing Reinforced Concrete Structures Using CFRP Fabrics”, 13th World Conference on Earthquake Engineering, Vancouver, B.C., Canada, paper no. 1393, 1-6 August 2004.
- Pan, C.L., Shan, M.Y., 2011, “Monotonic Shear Tests of Cold-Formed Steel Wall Frames with Sheathing”, Thin-Walled Structures, Vol. 49, No. 2, pp. 363-370.
- Suzuki, T., Choi, H., Sanada, Y., Nakano, Y., Kazuto Matsukawa, Devjyoti Paul, Gülkan, P., Binici, B., 2017, “Experimental Evaluation of The In-Plane Behaviour of Masonry Wall Infilled RC Frames”, Bulletin of Earthquake Engineering, Vol. 15, No. 10, pp. 4245-4267.
- Tankut, T., Ersoy, U., Ozcebe, G., Baran, M., Kuyucu, D., 2005, “In Service Seismic Strengthening of RC Framed Structures”, Seismic Assessment and Rehabilitation of Existing Buildings, International Closing Workshop, NATO Project Sfp., Vol. 977231, Istanbul, Turkey
- Wang, X., Ye, J., 2015, “Reversed Cyclic Performance of Cold-Formed Steel Shear Walls with Reinforced end Studs”, Journal of Constructional Steel Research, Vol. 113, pp. 28-42.
- Ye, J., Wang, X., Jia, H., Zhao, M., 2015, "Cyclic Performance of Cold-Formed Steel Shear Walls Sheathed with Double-Layer Wallboards on Both Sides", Thin-Walled Structures, Vol. 92, pp. 146-159.
- Yılmaz, Ü., Arslan, M.H., Kaltakcı, M.Y., 2010, “Betonarme Dış Perde Duvarla Güçlendirilmiş Çerçevelerin Dayanım Parametrelerinin Deneysel ve Analitik Yöntemlerle İrdelenmesi”, TÜBAV Bilim Dergisi, Vol. 3, No. 1, pp. 11-12.
- Zovkic, J., Sigmund, V., Guljas, I., 2013, “Cyclic Testing of a Single Bay Reinforced Concrete Frames with Various Types of Masonry Infill”, Earthquake engineering & structural dynamics, Vol. 42, No. 8, pp. 1131-1149.