autocad drawings of precast concrete cladding panels for - NEES

AUTOCAD DRAWINGS OF PRECASTCONCRETE CLADDING PANELS FORHIGH SEISMICITY REGIONAuthor: Diana LinHome Institution: San Jose State UniversityREU Institution: University of California, San DiegoPI: Tara C. HutchinsonMentor: Kurt McMullinOctober 10 th , 2011

Table of ContentsProject Overview .................................................................................................................................... 1Literature Review ................................................................................................................................... 2Contributions ........................................................................................................................................... 4AutoCAD .............................................................................................................................................. 4Construction Contributions................................................................................................................ 9Conclusion ............................................................................................................................................. 10Acknowledgements .............................................................................................................................. 11References ............................................................................................................................................ 12ii | P a g e

Project OverviewNatural disasters can happen at any time without warning. Damaged buildings andstructures can be dangerous for people. Dependent on how large the earthquake is,towns and cities can be destroyed in seconds. Engineers we must plan and design toensure that they create a structure that will not collapse because of an earthquake. Inaddition to building damage, earthquakes can cause severe damage to pipelines andcreate fire hazards. There has not been much research focusing on how fire hazardscan occur during and after an earthquake has taken place.The NEES site at UC San Diego will be testing a full scale five story reinforced concretecommercial building and its nonstructural components on the large outdoor shake tableunder the Principal Investigator Tara Hutchinson. This test will focus on thenonstructural components of the building and review in depth how fire safety hazardschange during an earthquake and post earthquake. While the building is shaking theobjects inside shake as well and many of the nonstructural components are torn off andthrown around the building. Gas pipes become damaged and leakage occurs, and withthe combination of hot light fixtures, fires can easily erupt and cause a chaotic inferno.Precast concrete panels provide a decorative coverage for the structure componentslike the slabs, beams and columns (McMullin et al, 2003). They are nonstructuralcomponents of a building because their self weight is supported on the frame structure.In the past, cladding panels have failed during an earthquake and have also causedmany deaths (Sielaff et al, 2005). For this NEES project, precast concrete claddingpanels were a recent addition and funding was not yet available for the system.NEES REU students from San Jose State University (SJSU) assisted the professors todevelop a proposal for funding. A proposal was being written to provide information tothe concrete cladding supplier. Various drawings were needed to help Professors TaraHutchinson and Kurt McMullin to show the cladding supplier how the design will look onthe current structure. Therefore, draft drawings were needed to show a visual layout ofthe panel placements and how panels were going to be connected to the frame.The five story reinforced concrete structure was already in the beginning phases ofconstruction when the SJSU team arrived on site. Figure 1 shows a 3 dimensionalmodel of the frame structure for the test specimen. The picture on the right is the samebuilding with concrete cladding panels. Panels will only be placed from the second floorto the roof.1 | P a g e

Figure 1: (Left) The structural system of the building used to test the nonstructural components (Right) the same buildingwith addition of the cladding panels (Drawn by Steve Mintz)Literature ReviewEngineers design the main frame of the structure. During the design process, differentloads are considered for design, including nonstructural components. Although loadsare considered for design, the main focus is ensuring that the structure will not collapsedue to gravity or lateral loads. Nonstructural components in the past were not designedfor moving forces like earthquakes. Examples of nonstructural components are pipingsystems which are used to transport water to different levels of the building, heatingventilation and air conditioning (HVAC) systems which are used regulating temperaturesin different rooms, and lighting fixtures that provide light to the building.When an earthquake occurs, the frame of the building moves side to side and causesan inertial force to act on the components. This force is similar to when one is in amoving vehicle that one’s body feels the force when the car accelerates and brakes(FEMA, 2005). Damage can occur to the nonstructural components during anearthquake when poor connections are made to the main structure. Figure 2 shows thedamage from the non structural components after the Northridge earthquake of 1994.Studs separated and caused the ceiling to collapse to the floor (FEMA, 2011).Concrete cladding panels can cause damage and in the past century, they have alsocaused deaths during earthquakes. Figure 3 shows the cladding panels at the JCPenney’s store that fell off the structure during the 1964 Alaska earthquake and causedtwo deaths (Arnold, 2009)..2 | P a g e

Figure 2: Damage to the nonstructural components due to incorrect metal stud partition (FEMA, 2011)Figure 3: J.C. Penney store in the 1964 Alaska earthquake caused concrete panels to fall (Arnold, 2009)New procedures were needed to help minimize damage and falling of concrete claddingpanels. In seismic regions, it is required that cladding panels have a Lateral Force-Resisting System (LFRS) and in addition, they have to have a flexible connection thatallows movements at the connection point (Maneetes & Memar, 2009). This has shownnot only improvements to the concrete cladding panels but it has brought benefits to theoverall structure. With flexible connections, panels have been able to resist wind andseismic forces (Li, 2010). This provides better performance during an earthquake3 | P a g e

ContributionsCladding panels were a new addition to the study of this five story reinforced concretebuilding to test the connections of the panels to the building. In addition, a fire test willbe completed after the earthquake test to examine how easily the fire will spread fromfloor to floor with the addition of the cladding panels.The NEES REU students on this project worked closely with Professors TaraHutchinson and Kurt McMullin to develop a proposal for funding for the claddingsystems. Two REU students were from UC San Diego who focused on the analysis ofthe cladding panels and ordering cladding supplies. The other two students were fromSan Jose State University and helped prepared detailed drawings of the claddingpanels and their connections for the supplier. Professor Kurt McMullin emailed handsketched drawings and called via phone to discuss how everything should look. Theteam provided him AutoCAD drawings based on his descriptions. Over the summer, theteam was able to produce approximately 80 different drawings.AutoCADEach week on Tuesday and Friday, the REU team from San Jose State had deadlinesto provide new and most updated AutoCAD drawings for Tara Hutchinson and KurtMcMullin. The importance of this was to ensure that when they had their meetings withthe Precast Concrete Institute (PCI), they had drawings to support their proposal.Although 80 drawings were completed, this paper focuses on six: an elevation view, afloor plan, an angle embedment plate, and three detail drawings of the installation of theembedment plates, a concrete panel, and the connect to the beam with the panel.Four different elevation views were needed for the building to show where and whattype of cladding panels will be needed. Figure 4 shows the south view of the buildingand all the panels that will be used. Each panel is labeled to indicate the different typesof panels that are needed. Spandrel Panel 1 (SP-1) will be used for the covering upmost of the slab edges. Spandrel Panel Returns (SR-1) will also be used to cover theslabs near the corners in addition to columns A and C. They are U-shaped panels andare mainly on the west and east views. Column Cover Long (CL-1) is placed to hidecolumn B while Column Cover Short (CS-1) is placed to hide half of the columns A andC. Column Cover Returns (CR-1) are L-shape panels that are wrapped around thecolumns A and C. When panels meet in between columns, a 2-inch seismic gap isneeded.4 | P a g e

Figure 4: Elevation of the south view of the NEES building for nonstructural componentsMore detailed drawings of the panels were needed to show how to attach them to themain structure. Figure 5 shows the interpretation of how the system will be installed;embedment plates (embeds) are located along the slab of the structure. This drawingshows the locations where the embedment plates will be installed from the centerline ofeach column. Steel embedment plates where used to provide a location to connect thecladding panels to the building. Figure 6 is a detailed drawing for the embedment plate5 | P a g e

Figure 5: A preliminary drawing of how the concrete cladding panels were to attach to the slab of the buildingFigure 6: Drawing of the angle embedment place on the slabs and beams to connect the cladding panels to the structure6 | P a g e

A detailed view of the installation of the angled embedment plates on the slabs isprovided on Figure 7. To secure the location of the plate when it is being cast into theconcrete slab, 180 degree hooks are looped around the stud. When the plates aresecured in place in the slab, connections can be made to attach the spandrel panels tothe structure.Figure 7: The installation of the angle embedment plates on the slabFigure 8 shows the different connections that will be placed on a spandrel panel. Thethree main connections will be the lateral seismic connection in the middle of the paneland two bearing connections on each side. Push-pull connections are also placed in thispanel because this will allow vertical correction due to the rod passing a large hole.7 | P a g e

Figure 8: Detail drawing of different connections placed on the spandrel panelsThe beam designs varied depending on the floor they were located on. Most beams hadthe top aligned and flush with the slab, but a new beam was being tested which was apartial upturn beam that was to be located on the second floor. In-depth drawings wereneeded to show how the two would differ because embedment plates were also placedon the beams to carry the cladding panels. Figure 9 shows the two different cases in thesection view. Since the beam is partial upturn, placement of the plates will be different.Drawings for the installation of the embedment plates for the upturn beam are still to bedetermined.8 | P a g e

Figure 9: Detail drawing of different layouts for each floor with different beamsThrough this AutoCAD experience I was able to understand working with numerousdeadlines in one week. Since deadlines were so critical for this project, there were manytimes that I had to bring the work home with me. I had to learn how to reach out toothers when I did not understand the concepts completely. First I would attempt thedrawing myself and when I got stuck, I asked my peers. We would work on it togetheruntil we both did not understand and our last option was to call our professor.Communication was difficult since he was out of the country. Through all the stress anddifficulties, I leave with in depth knowledge of the program.Construction ContributionsThe NEES REU students were out on site daily to provide assistance to the constructionof the building. Different minor tasks were needed to provide ease to both theconstruction workers and the PhD students. Some of the tasks were to inspect the steelbefore the day of concrete pouring, install strain gages on steel members, performslump tests for the concrete and prepare cylinders for concrete strength testing.Concrete pours for the structure were approximately twice a week. REU students werenotified a day in advance to prepare the area to create test cylinders of the concrete.For every concrete truck, 15 cylinders needed to be made. Typically there were twotrucks requiring a total of 30 test cylinders. Before cylinders and pouring could begin, a9 | P a g e

decided to take an alternative route and discard all the drawings that were made thissummer and have their drafters created new drawings. The frame is almost complete.When they have finished the nonstructural components can be placed on the structure.If all goes as planned, the structure is schedule to test Spring 2012. I hope to return towatch the testing of this great project I worked on this summer.AcknowledgementsThis is a project that was funded by the National Science Foundation CMMI-0936505. Iwould like to thank the NEES REU program (EEC 1005054) for providing this wonderfulprogram to undergraduate students. Thanks to the project PI Dr. Tara C. Hutchinson,San Jose State University Professor Kurt McMullin, the graduate and PhD students:Michelle Chen, Elide Pantoli, Steve Mintz, Elias Espino, Consuelo Aranda and DarjaHolz, the team at Englekirk and my fellow REU team on site: Cecilia Luu, Yujia Liu andYoshua Neuman. Thank you for the wonderful summer experience.11 | P a g e

ReferencesArnold, Chris 2009. Seismic Safety of the Building Envelope, National Institute ofbuilding Sciences Retrieved 8 Sept. 2011. Fromwww.wbdg.org/resources/env_seismicsafety.php?r=envelopeFEMA 2005 Earthquake Hazard for Mitigation for Nonstructural Elements (FEMA 74).United States: FEMA,FEMA 2011 Reducing Risk of Nonstructural Earthquake Damage (FEMA E-74) FourthEdition. United States: FEMALi, Jun Jie 2010. Earthquake Engineering Simulation With Flexible Cladding System.Thesis. University of Massachusetts,Maneetes, H., and Memar, A.M. 2009. Finite Element Modeling of Reinforced ConcreteCladding Panel. Electronic Journal of Structural Eng. V9McMullin, K., Chan, K., Choi, C., and Kwong, A. 2003 Performance Engineering ofPrecast Cladding SystemsSielaff, B.J., Nielsen, R.J., and Schmeckpeper, E.R. 2005. Evolution of Design CodeRequirements for Exterior Elements and Connections. Earthquake EngineeringResearch Institute. Earthquake Spectra. Volume 2112 | P a g e