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Problems with Buildings Lacking Basic Design Documentation
Available online at www.sciencedirect.com
ScienceDirect Procedia Engineering 195 (2017) 24 – 31
18th International Conference on Rehabilitation and Reconstruction of Buildings 2016, CRRB 2016
Problems with buildings lacking basic design documentation Marcin Chybińskia, Zdzisław Kurzawab, Łukasz Polusa,* a
Institute of Structural Engineering, Faculty of Civil and Environmental Engineering, Poznan University of Technology, Piotrowo 5, 60-965 Poznan, Poland b Polytechnic Faculty, The President Stanislaw Wojciechowski Higher Vocational State School in Kalisz, Poznanska 201-205, Kalisz, Poland
Abstract This paper discusses the problem of existing buildings which lack basic design documentation. This situation might have been caused by the old age of buildings or the loss of documentation. To solve this problem, time-consuming and expensive steps have to be taken, such as assessing the strength of construction materials, identifying loads, evaluating the technical state of structures and their strengthening. The authors present cases in which similar problems were solved. © 2017 2017The TheAuthors. Authors. Published by Elsevier © Published by Elsevier Ltd. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 18th International Conference on Rehabilitation and Peer-review underofresponsibility of the organizing committee of the 18th International Conference on Rehabilitation and Reconstruction Buildings 2016. Reconstruction of Buildings 2016
Keywords: steel structures; ultimate tensile strength; concrete structures
1. Introduction Civil engineers often prepare building regeneration, renovation or reinforcement projects, in which they encounter many problems. One of them is the lack of reliable data describing the used structural elements. This problem is really serious, because designers may have a problem with determining the durability and reliability of the buildings. In steel structures, it is most important to determine the steel grade, whereas in concrete structures, it is necessary to determine the compressive strength class, location and type of reinforcement. This can be achieved using certain
* Corresponding author. Tel.: +48 61 665-2098; fax: +48 61 876-6116. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 18th International Conference on Rehabilitation and Reconstruction of Buildings 2016
doi:10.1016/j.proeng.2017.04.519
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
tests. To evaluate the ultimate strength of steel, direct and indirect methods can be used [1]. Destructive tests may be employed when it is possible to take a sufficient number of samples from the construction. Samples and tests should be prepared using standard [2] to reliably estimate the tensile strength of steel. Sometimes it is impossible, because taking larger samples from the construction could reduce the load capacity. In such situations, a tensile strength test may be conducted using the MT5000H micro-tester on small samples from the construction [3, 4, 5]. It is also possible to use indirect non-destructive methods, in which the Brinell hardness of elements is measured. Knowing the relationship between the ultimate tensile strength and the hardness of steel it is easy to estimate the strength parameters of steel. This relationship is presented in [6, 7]. The authors of article [8] claim that said relationship is well known for the steel used in buildings from the second half of the 20th century. However, there is a problem with old steel found in structures that still exist and often need to be repaired and reinforced. When using the indirect method of estimating the strength parameters of old steel, the said authors proposed to rely on numerous hardness measurements and to broaden the analysis of chemical composition. The compressive strength class of concrete can be determined using destructive or non-destructive methods. When it is not possible to take a sufficient number of samples from the construction, non-destructive tests may be done. One of the most popular non-destructive tools of concrete testing is the Schmidt rebound hammer, which is a surface hardness tester [9]. Knowing the relationship between the compressive strength of concrete and the rebound number of the hammer, it is possible to estimate the strength parameter of concrete. However, the authors of article [10] pointed out that the Schmidt rebound hammer is not a tool for directly estimating the concrete strength. The authors of article [11] suggested that it is possible to directly determine the approximate value of compressive strength from the rebound number when the rebound hammer conversion chart is used. Reinforcement can be located using a special scanner. When old prefabricated halls are analysed, the old catalogues like [12, 13] may be used to identify structural elements. However, today civil engineers should be careful, because during the construction of buildings in the 60’s – 80’s their predecessors often made changes in structural elements because of the lack of materials, for example they sometimes used different reinforcement than shown in the catalogue. Nomenclature ReHi ReHd Rmi Rmd
yield strength obtained using indirect methods yield strength obtained using direct methods ultimate tensile strength obtained using indirect methods ultimate tensile strength obtained using direct methods
2. Examples 2.1. A steel and concrete hall lacking design documentation The first example is a multi-bay hall (see Fig. 1). It was an unfinished production and storage hall, because its construction had been stopped. Several years later, a new investor decided to finish it and to change the purpose of the hall. However, the data regarding structural elements had been lost. The most important part of the building is presented in Figure 2a. It was the bay with the greatest span and with runway beams for a 35 t crane. The hall consisted of frames made of reinforced concrete, non-prismatic columns with rigid bases and steel trusses (34.0 meters long) joined with columns using pinned connections. The columns were non-prismatic, because on their lower parts runway beams were installed. Truss purlins were supported by main frames spaced every 12.0 meters. On the purlins steel sheeting was used as roof cladding. In the roof, there was a dome skylight. The hall also had roof bracing and vertical bracing in the walls, which is not presented in Figure 2. The documentation had to be reconstructed. It was easy to identify the structural elements, type of reinforcement and compressive strength class of concrete. However, there was a problem with determining grade of steel. The initial static calculations, in which grade St3S (S235) of steel was assumed, proved that structural elements had insufficient load bearing capacity. To solve this problem, the strength of steel should have been assessed, but the authors had no permission to take standard samples. Therefore, four round samples (40 mm in diameter) were taken from the construction (see Fig. 3).
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Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
Each sample was tested using the Vickers HV 0.5 harness test (Vickers Micromet 2104 harness tester) and the tensile strength test (MT5000H micro-tester). The Vickers hardness was converted to the Brinell scale. Next, having determined the relationship between the ultimate tensile strength and the hardness of steel it was easy to estimate yield strength and the ultimate tensile strength thereof. a
b
Fig. 1. (a) reinforced concrete columns and steel trusses; (b) crane with runway beams.
a
b
c
Fig. 2. (a) production hall; (b) using longitudinal trusses as supports for added trusses; (c) using runway beams as supports for added trusses.
27
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
a
b
Fig. 3. (a) hole in the element; (b) sample after test.
The calculated parameters were then compared. The difference between the results obtained using indirect and direct methods ranged from 1.1 % to 15 % (see Table 1). To minimize the difference, more samples should have been tested. Table 1. The yield strength and ultimate tensile strength obtained from tests Sample 1 2 3 4
ReHi MPa 326 429 404 382
ReHd MPa 277 449 429 394
(ReHi-ReHd)/ ReHi % 15.0 4.7 6.2 3.1
Rmi MPa 475 626 590 557
Rmd MPa 434 555 602 563
(Rmi-Rmd)/ Rmi % 8.6 11.3 9.8 1.1
It was easy to determine the steel grade of the first sample – St3S (S235). However, there was a problem with the remaining three samples. They contained the same steel, but could be classified both as grade St4 (S275) steel and as grade 18G2 (S355) steel. To determine the steel grade beyond any doubt, a standard test should have been done in the next stage. However, the investor stopped right after this stage. Given the small number of tests, insufficient to conduct statistical analysis and to draw general conclusions, the authors suggested strengthening the construction in order to solve this problem. The suggestion is presented in Figure 3. The first option was to strengthen all structural elements, but it was too expensive, in particular because the work would have to be done at the construction site. The second option was to remove the steel sheeting and truss purlins and add trusses between main frames. This had two suboptions. The first suboption consisted in the use of two types of trusses which were added. The trusses parallel to the main frame were supported by the trusses connecting the columns (see Fig. 2b). This suboption allowed the use of a crane. The second suboption made impossible to use a crane, because the runway beams were used as supports for the additional trusses (see Fig. 2c). The crane could have been replaced by forklifts. The investor could choose the most desirable solution. 2.2. A concrete hall lacking design documentation The lack of basic design documentation was also a problem in the case of a concrete hall which was built in the 60’s of the 20th century using prefabricated reinforced concrete elements. The building was old and its documentation had been lost. The system of the hall was similar to the existing Polish system of prefabricated halls, such as P-70 but there were differences in dimensions and reinforcement, perhaps it was a prototype. There were cranes which could lift 4.5 t (see Fig. 4 and 5a), however, the investor wanted to install an overhead travelling crane which could lift up to 15 t.
28
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
a
b
Fig. 4. (a) prefabricated hall; (b) crane with runway beams.
a
b
c
d
Fig. 5. (a) concrete prefabricated hall; (b) trestle bridge connected with existing building; (c) trestle bridge not connected with existing building; (d) gantry crane installed in the hall.
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
Some tests were conducted to determine the resistance of the prefabricated reinforced concrete runway beam. The concrete was tested using the Schmidt rebound hammer. A special scanner was used to locate reinforcement and a small part of the beam was destroyed to measure the diameters of the bars (see Fig. 6). a
b
Fig. 6. (a) 1-bar, 2- stirrup; (b) location of stirrups.
The runway T-beams were 60 cm high and they were simply supported. Main reinforcement of the beam consisted of 3 plain bars with a diameter of 25 mm. As a result of calculation, the resistance of the beam was not enough for 15 t crane. The prefabricated runway beams had been designed for 4.5 t crane. It was possible to use 8 t crane, but the wheel track of end carriage should have had 3.0 meters long. To lift 15 t a gantry crane or a trestle bridge should have been installed. The steel beams from the trestle should not be supported by existing concrete columns (see Fig. 5b). In this suggestion static calculation should be made for the whole hall using current standards and the hall should be strengthened. For this reason, the gantry crane and the trestle bridge should be not connected with the existing building (see Fig. 5c and 5d). 3. Procedure with buildings lacking basic design documentation The examples presented in point two showed that the lack of documentation may impede the modernization or rebuilding of existing buildings. Thanks to the analysis of these examples, the authors prepared the procedure for buildings lacking basic design documentation. This procedure makes it possible to avoid mistakes during the analyses of similar buildings and excessive costs connected with the modernization or rebuilding of these buildings. Moreover, the investor may organize his actions in this process. The algorithm should take into account the evaluation of the technical state of structures and the reconstruction of documentation and should consists of: Stage 1: 1.1. Assessment of the strength of construction materials, 1.2. Identification of loads, 1.3. Cataloguing of structural elements and their connections, 1.4. Identification and evaluation of imperfections, 1.5. Reconstruction of documentation, 1.6. Determination of the calculation model and analysing the existing building taking into account the previous steps and additional loads, 1.7. Conclusions regarding the technical state of structures, 1.8. Finishing the procedure after stage 1 or moving to stage 2: ‒ if the static calculations taking into account the actual loads, material properties and the technical state of the building prove that the structural elements have a load-bearing capacity reserve and the building will not be rebuilt, it should stay in an existing state, ‒ if the technical state of the building is bad or too expensive to repair, the building should be deconstructed, ‒ if the static calculations do not prove that the structural elements have a load bearing capacity reserve, stage 2 should be implemented.
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Stage 2: 2.1. Analysing the possible rebuilding/modernization or strengthening of the building, 2.2. Analysing economic costs connected with the suggested solutions: ‒ changing the purpose of the object, e.g. a production hall with cranes could be turned into a storage hall without the use of cranes, ‒ strengthening the structural elements, e.g. changing the characteristics of the cross-section: increasing the surface area, the radiuses of gyration and reducing the slenderness of elements; changing the stability of the cross-section walls using additional stiffeners; adding parts to cross-section to reduce its class, ‒ reducing loads, e.g. changing the wheel track of end carriage of the crane, the working area of the crane, the weight of the crane or reduce the load which the crane may lift, replacing overhead cranes with gantry cranes or forklifts, adding columns as supports for beams, replacing heavy roof or wall cladding to light, ‒ rebuilding and changing the static scheme of the building, e.g. adding supports, bracing, changing connections from pinned to fixed or inversely to obtain the favourable force distribution. 2.3. Choosing the most desirable solution and designing the project. 4. Conclusion The problem of existing buildings which lack basic design documentation is really serious and current, in particular because designers may have a problem with determining the durability and reliability of the buildings. The durability and reliability are important factors that cannot be ignored when designing of buildings and using european standards like [14, 15, 16]. These factors are equally important during execution of the structures [17, 18]. The identification of materials should be done during all stages of the execution of the structural elements (production, delivery to the construction site, assembly of construction). Not only an investor should keep documentation, but also a company which products structural elements. What is more, CE marking for structural steel is mandatory for products sold on the EU construction market. Thanks to these standards and harmonised technical rules newly built industrial buildings may be without the lack of reliable data describing the used structural elements. The article shows, that it is very important to keep documentation, because it may reduce costs of rebuilding or modernization in the future. If designers encounter problem with the lack of reliable data describing the used structural elements, they may solve this problem using special procedure presented in this article. This procedure may help to avoid mistakes and may reduce cost during the rebuilding or modernization of the existing buildings. References [1] B. Gosowski, P. Organek, Direct and indirect ways of determining ultimate strength of steel used in building structures [in Polish], Building Materials 3 (2014) 56-59. [2] ISO 6892-1:2016, Metallic materials, Tensile testing, Part 1: Method of test at room temperature. [3] D. Garbiec, M. Jurczyk, Al-SiC composites synthesized by the spark plasma sintering method (SPS), Composites Theory and Practice 13:4 (2013) 255-259. [4] D. Garbiec, M. Jurczyk, N. Levintant-Zayonts, T. Mościcki, Properties of Al–Al2O3 composites synthesized by spark plasma sintering method, Archives of Civil and Mechanical Engineering 15:4 (2015) 933-939. [5] M. Pawlicki, T. Drenger, M. Pieszak, J. Borowski, Cold upset forging joining of ultra-fine-grained aluminium and copper, Journal of Materials Processing Technology 223 (2015) 193-202. [6] J. Dudkiewicz, B. Gosowski, Generalizations of relations between strength and hardness of steel in structural elements under longitudinal load, Archives of Civil Engineering L, 1 (2004) 47-67. [7] B. Gosowski, E. Kubica, Laboratory tests on metal structures [in Polish], Wroclaw University of Technology Publishing House, Wroclaw, 2001. [8] B. Gosowski, P. Organek, Use of the hardness test in-situ for evaluation of strength of steel from the early 20th century, 2-4 July 2014, KielceSuchedniow, Poland [9] S. Rubene, M. Vilnitis, Use of the Schmidt rebound hammer for non-destructive concrete structure testing in field, Civil Engineering 1-B (2014) 13-19. [10] A. Brencich, G. Cassini, D. Pera, G. Riotto, Calibration and Reliability of the Rebound (Schmidt) Hammer Test, Civil Engineering and Architecture 1(3) (2013) 66-78.
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31 [11] A. Jain, A. Kathuria, A. Kumar, Y. Verma, K. Murari, Combined Use of Non-Destructive Tests for Assessment of Strength of Concrete in Structure, Procedia Engineering 54 ( 2013 ) 241 – 251. [12] A. Głowski, Crane runway beams [in Polish], Handbook for design, Warszawa, 1963. [13] Z. Wasiukiewicz, M. Wolski, P-70, System of construction and assembly of reinforced concrete prefabricated industrial halls, Arkady, 1976. [14] EN 1990:2002, Eurocode: Basis of structural design. [15] EN 1992-1-1:2004, Eurocode 2: Design of concrete structures. Part 1-1: General rules and rules for buildings. [16] EN 1993-1-1:2005, Eurocode 3: Design of steel structures. Part 1-1: General rules and rules for buildings. [17] EN 1090-1:2009, Execution of steel structures and aluminium structures. Part 1: Requirements for conformity assessment of structural components. [18] EN 1090-2:2008, Execution of steel structures and aluminium structures. Part 2: Technical requirements for steel structures.
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ScienceDirect Procedia Engineering 195 (2017) 24 – 31
18th International Conference on Rehabilitation and Reconstruction of Buildings 2016, CRRB 2016
Problems with buildings lacking basic design documentation Marcin Chybińskia, Zdzisław Kurzawab, Łukasz Polusa,* a
Institute of Structural Engineering, Faculty of Civil and Environmental Engineering, Poznan University of Technology, Piotrowo 5, 60-965 Poznan, Poland b Polytechnic Faculty, The President Stanislaw Wojciechowski Higher Vocational State School in Kalisz, Poznanska 201-205, Kalisz, Poland
Abstract This paper discusses the problem of existing buildings which lack basic design documentation. This situation might have been caused by the old age of buildings or the loss of documentation. To solve this problem, time-consuming and expensive steps have to be taken, such as assessing the strength of construction materials, identifying loads, evaluating the technical state of structures and their strengthening. The authors present cases in which similar problems were solved. © 2017 2017The TheAuthors. Authors. Published by Elsevier © Published by Elsevier Ltd. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 18th International Conference on Rehabilitation and Peer-review underofresponsibility of the organizing committee of the 18th International Conference on Rehabilitation and Reconstruction Buildings 2016. Reconstruction of Buildings 2016
Keywords: steel structures; ultimate tensile strength; concrete structures
1. Introduction Civil engineers often prepare building regeneration, renovation or reinforcement projects, in which they encounter many problems. One of them is the lack of reliable data describing the used structural elements. This problem is really serious, because designers may have a problem with determining the durability and reliability of the buildings. In steel structures, it is most important to determine the steel grade, whereas in concrete structures, it is necessary to determine the compressive strength class, location and type of reinforcement. This can be achieved using certain
* Corresponding author. Tel.: +48 61 665-2098; fax: +48 61 876-6116. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 18th International Conference on Rehabilitation and Reconstruction of Buildings 2016
doi:10.1016/j.proeng.2017.04.519
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
tests. To evaluate the ultimate strength of steel, direct and indirect methods can be used [1]. Destructive tests may be employed when it is possible to take a sufficient number of samples from the construction. Samples and tests should be prepared using standard [2] to reliably estimate the tensile strength of steel. Sometimes it is impossible, because taking larger samples from the construction could reduce the load capacity. In such situations, a tensile strength test may be conducted using the MT5000H micro-tester on small samples from the construction [3, 4, 5]. It is also possible to use indirect non-destructive methods, in which the Brinell hardness of elements is measured. Knowing the relationship between the ultimate tensile strength and the hardness of steel it is easy to estimate the strength parameters of steel. This relationship is presented in [6, 7]. The authors of article [8] claim that said relationship is well known for the steel used in buildings from the second half of the 20th century. However, there is a problem with old steel found in structures that still exist and often need to be repaired and reinforced. When using the indirect method of estimating the strength parameters of old steel, the said authors proposed to rely on numerous hardness measurements and to broaden the analysis of chemical composition. The compressive strength class of concrete can be determined using destructive or non-destructive methods. When it is not possible to take a sufficient number of samples from the construction, non-destructive tests may be done. One of the most popular non-destructive tools of concrete testing is the Schmidt rebound hammer, which is a surface hardness tester [9]. Knowing the relationship between the compressive strength of concrete and the rebound number of the hammer, it is possible to estimate the strength parameter of concrete. However, the authors of article [10] pointed out that the Schmidt rebound hammer is not a tool for directly estimating the concrete strength. The authors of article [11] suggested that it is possible to directly determine the approximate value of compressive strength from the rebound number when the rebound hammer conversion chart is used. Reinforcement can be located using a special scanner. When old prefabricated halls are analysed, the old catalogues like [12, 13] may be used to identify structural elements. However, today civil engineers should be careful, because during the construction of buildings in the 60’s – 80’s their predecessors often made changes in structural elements because of the lack of materials, for example they sometimes used different reinforcement than shown in the catalogue. Nomenclature ReHi ReHd Rmi Rmd
yield strength obtained using indirect methods yield strength obtained using direct methods ultimate tensile strength obtained using indirect methods ultimate tensile strength obtained using direct methods
2. Examples 2.1. A steel and concrete hall lacking design documentation The first example is a multi-bay hall (see Fig. 1). It was an unfinished production and storage hall, because its construction had been stopped. Several years later, a new investor decided to finish it and to change the purpose of the hall. However, the data regarding structural elements had been lost. The most important part of the building is presented in Figure 2a. It was the bay with the greatest span and with runway beams for a 35 t crane. The hall consisted of frames made of reinforced concrete, non-prismatic columns with rigid bases and steel trusses (34.0 meters long) joined with columns using pinned connections. The columns were non-prismatic, because on their lower parts runway beams were installed. Truss purlins were supported by main frames spaced every 12.0 meters. On the purlins steel sheeting was used as roof cladding. In the roof, there was a dome skylight. The hall also had roof bracing and vertical bracing in the walls, which is not presented in Figure 2. The documentation had to be reconstructed. It was easy to identify the structural elements, type of reinforcement and compressive strength class of concrete. However, there was a problem with determining grade of steel. The initial static calculations, in which grade St3S (S235) of steel was assumed, proved that structural elements had insufficient load bearing capacity. To solve this problem, the strength of steel should have been assessed, but the authors had no permission to take standard samples. Therefore, four round samples (40 mm in diameter) were taken from the construction (see Fig. 3).
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Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
Each sample was tested using the Vickers HV 0.5 harness test (Vickers Micromet 2104 harness tester) and the tensile strength test (MT5000H micro-tester). The Vickers hardness was converted to the Brinell scale. Next, having determined the relationship between the ultimate tensile strength and the hardness of steel it was easy to estimate yield strength and the ultimate tensile strength thereof. a
b
Fig. 1. (a) reinforced concrete columns and steel trusses; (b) crane with runway beams.
a
b
c
Fig. 2. (a) production hall; (b) using longitudinal trusses as supports for added trusses; (c) using runway beams as supports for added trusses.
27
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
a
b
Fig. 3. (a) hole in the element; (b) sample after test.
The calculated parameters were then compared. The difference between the results obtained using indirect and direct methods ranged from 1.1 % to 15 % (see Table 1). To minimize the difference, more samples should have been tested. Table 1. The yield strength and ultimate tensile strength obtained from tests Sample 1 2 3 4
ReHi MPa 326 429 404 382
ReHd MPa 277 449 429 394
(ReHi-ReHd)/ ReHi % 15.0 4.7 6.2 3.1
Rmi MPa 475 626 590 557
Rmd MPa 434 555 602 563
(Rmi-Rmd)/ Rmi % 8.6 11.3 9.8 1.1
It was easy to determine the steel grade of the first sample – St3S (S235). However, there was a problem with the remaining three samples. They contained the same steel, but could be classified both as grade St4 (S275) steel and as grade 18G2 (S355) steel. To determine the steel grade beyond any doubt, a standard test should have been done in the next stage. However, the investor stopped right after this stage. Given the small number of tests, insufficient to conduct statistical analysis and to draw general conclusions, the authors suggested strengthening the construction in order to solve this problem. The suggestion is presented in Figure 3. The first option was to strengthen all structural elements, but it was too expensive, in particular because the work would have to be done at the construction site. The second option was to remove the steel sheeting and truss purlins and add trusses between main frames. This had two suboptions. The first suboption consisted in the use of two types of trusses which were added. The trusses parallel to the main frame were supported by the trusses connecting the columns (see Fig. 2b). This suboption allowed the use of a crane. The second suboption made impossible to use a crane, because the runway beams were used as supports for the additional trusses (see Fig. 2c). The crane could have been replaced by forklifts. The investor could choose the most desirable solution. 2.2. A concrete hall lacking design documentation The lack of basic design documentation was also a problem in the case of a concrete hall which was built in the 60’s of the 20th century using prefabricated reinforced concrete elements. The building was old and its documentation had been lost. The system of the hall was similar to the existing Polish system of prefabricated halls, such as P-70 but there were differences in dimensions and reinforcement, perhaps it was a prototype. There were cranes which could lift 4.5 t (see Fig. 4 and 5a), however, the investor wanted to install an overhead travelling crane which could lift up to 15 t.
28
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
a
b
Fig. 4. (a) prefabricated hall; (b) crane with runway beams.
a
b
c
d
Fig. 5. (a) concrete prefabricated hall; (b) trestle bridge connected with existing building; (c) trestle bridge not connected with existing building; (d) gantry crane installed in the hall.
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31
Some tests were conducted to determine the resistance of the prefabricated reinforced concrete runway beam. The concrete was tested using the Schmidt rebound hammer. A special scanner was used to locate reinforcement and a small part of the beam was destroyed to measure the diameters of the bars (see Fig. 6). a
b
Fig. 6. (a) 1-bar, 2- stirrup; (b) location of stirrups.
The runway T-beams were 60 cm high and they were simply supported. Main reinforcement of the beam consisted of 3 plain bars with a diameter of 25 mm. As a result of calculation, the resistance of the beam was not enough for 15 t crane. The prefabricated runway beams had been designed for 4.5 t crane. It was possible to use 8 t crane, but the wheel track of end carriage should have had 3.0 meters long. To lift 15 t a gantry crane or a trestle bridge should have been installed. The steel beams from the trestle should not be supported by existing concrete columns (see Fig. 5b). In this suggestion static calculation should be made for the whole hall using current standards and the hall should be strengthened. For this reason, the gantry crane and the trestle bridge should be not connected with the existing building (see Fig. 5c and 5d). 3. Procedure with buildings lacking basic design documentation The examples presented in point two showed that the lack of documentation may impede the modernization or rebuilding of existing buildings. Thanks to the analysis of these examples, the authors prepared the procedure for buildings lacking basic design documentation. This procedure makes it possible to avoid mistakes during the analyses of similar buildings and excessive costs connected with the modernization or rebuilding of these buildings. Moreover, the investor may organize his actions in this process. The algorithm should take into account the evaluation of the technical state of structures and the reconstruction of documentation and should consists of: Stage 1: 1.1. Assessment of the strength of construction materials, 1.2. Identification of loads, 1.3. Cataloguing of structural elements and their connections, 1.4. Identification and evaluation of imperfections, 1.5. Reconstruction of documentation, 1.6. Determination of the calculation model and analysing the existing building taking into account the previous steps and additional loads, 1.7. Conclusions regarding the technical state of structures, 1.8. Finishing the procedure after stage 1 or moving to stage 2: ‒ if the static calculations taking into account the actual loads, material properties and the technical state of the building prove that the structural elements have a load-bearing capacity reserve and the building will not be rebuilt, it should stay in an existing state, ‒ if the technical state of the building is bad or too expensive to repair, the building should be deconstructed, ‒ if the static calculations do not prove that the structural elements have a load bearing capacity reserve, stage 2 should be implemented.
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Stage 2: 2.1. Analysing the possible rebuilding/modernization or strengthening of the building, 2.2. Analysing economic costs connected with the suggested solutions: ‒ changing the purpose of the object, e.g. a production hall with cranes could be turned into a storage hall without the use of cranes, ‒ strengthening the structural elements, e.g. changing the characteristics of the cross-section: increasing the surface area, the radiuses of gyration and reducing the slenderness of elements; changing the stability of the cross-section walls using additional stiffeners; adding parts to cross-section to reduce its class, ‒ reducing loads, e.g. changing the wheel track of end carriage of the crane, the working area of the crane, the weight of the crane or reduce the load which the crane may lift, replacing overhead cranes with gantry cranes or forklifts, adding columns as supports for beams, replacing heavy roof or wall cladding to light, ‒ rebuilding and changing the static scheme of the building, e.g. adding supports, bracing, changing connections from pinned to fixed or inversely to obtain the favourable force distribution. 2.3. Choosing the most desirable solution and designing the project. 4. Conclusion The problem of existing buildings which lack basic design documentation is really serious and current, in particular because designers may have a problem with determining the durability and reliability of the buildings. The durability and reliability are important factors that cannot be ignored when designing of buildings and using european standards like [14, 15, 16]. These factors are equally important during execution of the structures [17, 18]. The identification of materials should be done during all stages of the execution of the structural elements (production, delivery to the construction site, assembly of construction). Not only an investor should keep documentation, but also a company which products structural elements. What is more, CE marking for structural steel is mandatory for products sold on the EU construction market. Thanks to these standards and harmonised technical rules newly built industrial buildings may be without the lack of reliable data describing the used structural elements. The article shows, that it is very important to keep documentation, because it may reduce costs of rebuilding or modernization in the future. If designers encounter problem with the lack of reliable data describing the used structural elements, they may solve this problem using special procedure presented in this article. This procedure may help to avoid mistakes and may reduce cost during the rebuilding or modernization of the existing buildings. References [1] B. Gosowski, P. Organek, Direct and indirect ways of determining ultimate strength of steel used in building structures [in Polish], Building Materials 3 (2014) 56-59. [2] ISO 6892-1:2016, Metallic materials, Tensile testing, Part 1: Method of test at room temperature. [3] D. Garbiec, M. Jurczyk, Al-SiC composites synthesized by the spark plasma sintering method (SPS), Composites Theory and Practice 13:4 (2013) 255-259. [4] D. Garbiec, M. Jurczyk, N. Levintant-Zayonts, T. Mościcki, Properties of Al–Al2O3 composites synthesized by spark plasma sintering method, Archives of Civil and Mechanical Engineering 15:4 (2015) 933-939. [5] M. Pawlicki, T. Drenger, M. Pieszak, J. Borowski, Cold upset forging joining of ultra-fine-grained aluminium and copper, Journal of Materials Processing Technology 223 (2015) 193-202. [6] J. Dudkiewicz, B. Gosowski, Generalizations of relations between strength and hardness of steel in structural elements under longitudinal load, Archives of Civil Engineering L, 1 (2004) 47-67. [7] B. Gosowski, E. Kubica, Laboratory tests on metal structures [in Polish], Wroclaw University of Technology Publishing House, Wroclaw, 2001. [8] B. Gosowski, P. Organek, Use of the hardness test in-situ for evaluation of strength of steel from the early 20th century, 2-4 July 2014, KielceSuchedniow, Poland [9] S. Rubene, M. Vilnitis, Use of the Schmidt rebound hammer for non-destructive concrete structure testing in field, Civil Engineering 1-B (2014) 13-19. [10] A. Brencich, G. Cassini, D. Pera, G. Riotto, Calibration and Reliability of the Rebound (Schmidt) Hammer Test, Civil Engineering and Architecture 1(3) (2013) 66-78.
Marcin Chybiński et al. / Procedia Engineering 195 (2017) 24 – 31 [11] A. Jain, A. Kathuria, A. Kumar, Y. Verma, K. Murari, Combined Use of Non-Destructive Tests for Assessment of Strength of Concrete in Structure, Procedia Engineering 54 ( 2013 ) 241 – 251. [12] A. Głowski, Crane runway beams [in Polish], Handbook for design, Warszawa, 1963. [13] Z. Wasiukiewicz, M. Wolski, P-70, System of construction and assembly of reinforced concrete prefabricated industrial halls, Arkady, 1976. [14] EN 1990:2002, Eurocode: Basis of structural design. [15] EN 1992-1-1:2004, Eurocode 2: Design of concrete structures. Part 1-1: General rules and rules for buildings. [16] EN 1993-1-1:2005, Eurocode 3: Design of steel structures. Part 1-1: General rules and rules for buildings. [17] EN 1090-1:2009, Execution of steel structures and aluminium structures. Part 1: Requirements for conformity assessment of structural components. [18] EN 1090-2:2008, Execution of steel structures and aluminium structures. Part 2: Technical requirements for steel structures.
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