concrete podium deck construction

By James Cooper, P.Eng., LEED AP O+M Owners, engineers, and contractors involved in the design, operation, maintenance, and restoration of parking garages and building podium decks … This 109,600 square-foot student housing project includes five stories of wood-frame construction over a concrete podium … 1 0 obj endobj A fast, … 20 0 obj All materials contained in this website fall under U.S. copyright laws. In North America, “podium” buildings, which include multiple stories of wood over an elevated concrete “podium deck,” have become especially prevalent. Item e of ASCE 7 / 12.3.3.2 mentioned that lower portion is analyzed with the equivalent lateral force procedure. Usually these slabs are … Connection requirements to the podium slab are shown in Figure 4. And, although concrete is inherently durable, leaving it unprotected is an invitation for premature deterioration. However, some newer systems have been developed with lighter residential construction in mind. covers the entire building. Podium decks … Seismic and Wind Load Considerations. Comprised of three separate four-story wood buildings, two of which sit on a 50,000-square-foot post-tensioned concrete podium deck, the project used 18-inch deep open web trusses. Nationwide, there has been an increase in the demand for multi-story mixed-use and multi-residential structures. Most industry standards require 1 to 2% slopes to address drainage issues of podium decks. The concrete subcontractor poured the concrete decks to finish floor elevation, not to deck thickness which is required per note CP‐4. Podium construction can be an efficient and cost-effective way to meet the rapidly growing demand for student housing across the country. 3 podIum and/or parkIng roof decks combIned wIth IntensIve green roofs 4 nophadraIn podIum deck and p arkIng deck systems 4.1 Podium Deck System – load class 1 Warm roof construction/roof construction without thermal insulation a. Build-up without sub-base layer b. Build-up including sub-base layer c. Build-up including levelling layer <> 3 podIum and/or parkIng roof decks combIned wIth IntensIve green roofs 4 nophadraIn podIum deck and p arkIng deck systems 4.1 Podium Deck System – load class 1 Warm roof construction/roof construction … An R-2 occupancy above a Type 1-A construction, parking garage. Decks with higher slopes can remove water faster from the deck … Long span steel construction at the podium level provides more flexible use of space below, which depends on the function of the building : The lightweight nature of the steel structure of the upper residential levels minimises the loads on the podium level and therefore saves on the cost of the podium structure Types of residential buildings. This type of construction in which the building elements listed in IBC Table 601 are of non-combustible materials, such as concrete and steel. Distribution of forces to the vertical resisting elements are based on analysis methods where the diaphragm is modeled as follows: Current practice for light-frame construction commonly assumes that wood diaphragms are flexible for the purpose of distributing horizontal forces to shear walls. The focus of the review should be to understand the age and effectiveness of the podium deck waterproofing system by determining the extent of leakage and concrete deterioration below, … Reprinting or other use of these materials without express permission of NCSEA is prohibited. Another consideration is the detailing and added framing challenge of placing the interior wall sheathing between or behind the joist hangers. And, although concrete is inherently durable, leaving it unprotected is an invitation for premature deterioration. The challenge The Water Gardens … endobj Founded in 1994, we have over 25 years of industry experience and comprehensive market knowledge. The building portions are separated by a horizontal assembly with a minimum 3-hour fire resistance rating. In multifamily residential structures, a concrete Podium Slab typically acts as both a structural floor and as a transfer slab for wood and light gauge steel framed construction above. Concrete … Continuous tie-rod systems with shrinkage-compensating devices are becoming the preferred method of anchoring for multiple narrow stacked shear walls because they account for vertical shrinkage at each floor level and provide better control over story drift. Only the weight of the flexible upper portion has to be considered in its design, not the entire weight of both portions. My question will the R-2’s be protected with an NFPA 13 or 13R system. I have had the incredible pleasure of overseeing some of the most creative and dedicated workers any CEO could hope for. 11 0 obj Podium slab construction techniques. podium deck. W. R. MEADOWS is proud to announce that 2021 marks our milestone 95th year of business operation. 8 0 obj The requirements for a two-stage analysis are: a) The stiffness of the lower section is ten times the stiffness of the upper section. New studies and discussions are taking place to consider including the effects of wall bending and rotation of the walls acting together as a unit, as will be discussed in Part 2 of this article. �t} �lK5mH7M�U��iG��ҘV׹�l��t��i\�I1�i�q�'�E�dʦ��1�j9�vholB�9B�.M��fL�-z7�j��n6� � �Z�*��r�ƽ�큂��j� sΠ[�J�� 19 0 obj STRUCTURE magazine is the premier resource for practicing structural engineers. Five Story Wood-frame Structure Over Podium Slab. Figure 5. Typical projects include building structures consisting of reinforced or post-tensioned concrete slabs with wood frame construction and stucco exteriors, and several completed projects feature podium decks. The number of boundary studs on the compression side of the wall are often controlled by these stresses. endobj The Polyurea system has been developed over the last 20 years for use in the waterproofing industry for concrete decks, reservoir roofs, bunds, top of basement wall detailing green roofs as well as lorry beds, ships hulls and bridges. Rooftop and podium concrete decks are used for car parks, equipment plants, and similar situations. Sacramento, CA, SEAOC/IBC Structural Design Manual, Volume 2. Next, once all the floors are reviewed, areas of the building are defined for non-typical (Podium … - type of construction only for wood-framed buildings on top of podium. Combining light-framed shear walls sheathed with other materials (e.g. American Forest and Paper Association (AF & PA). How Full Can Concrete Trucks be when Driving on Slabs-on-Grade? <> This must be accounted for in the design and can in some cases increase the size of the studs. <> endobj 7 0 obj Deck Footings. So whether the podium is required to support multi-level conventional residential construction or a green roof with outdoor amenities, embarking on the design must begin with selecting 16” NiCore™ Plank from Nitterhouse Concrete Products, Inc. in Chambersburg, PA, a family-owned company serving the construction … <> We are designing a 4 story residential building with the first level being composite steel framed with concrete filled metal deck and then 3 level of wood construction. Two types of anchoring systems can be used as shown in Figure 5, discrete hold downs and continuous tie-rod anchoring systems. This allowance only applies when: In versions of the IBC up to and including 2012, the lower portion of the construction described by these provisions, commonly referred to as the podium, can be no more than one story above the grade plane. %PDF-1.5 This article covers important design considerations and traditional approaches related to the design of a five-story wood-framed structure over a two-story concrete or masonry podium. offices, restaurants, retail ... steel deck with a reinforced concrete fill ) that . Recent Blog Posts. endobj This design would likely be most cost-effective when the building has no need for a parking deck and ample space in the lot on which it is being built. Sacramento, CA. He is the author of The Analysis of Irregular Shaped Structures: Diaphragms and Shear Walls, published by McGraw-Hill and ICC. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> stream Figure 4. Load bearing elements such as walls and columns of superstructure above the podium slab may not align with substructure load bearing elements below. Emmerson’s developments exceed Title 24 efficiency standards and over a dozen projects have been certified LEED Gold or Platinum. Single Family. Now that you know the benefits of building with a post-tensioned concrete podium, you may want to know how to go about. º Water resistant concrete 1.6 Details 1.7 Design of falls - structural roof deck 1.8 Roof drainage • Stormwater discharge via gravity drainage inside a building - roof outlets • Linear drainage channel • Stormwater discharge over roof egde • Surface water from adjacent roofs and facades 2.1 Separation layer 2.2 Slip layer 2.3 Protection layer 2.4 9Drainage layer 2.5 Filter layer 2.6 Overturning forces are typically determined by dividing the sum of the moment applied at the top of the wall by the distance between the center of the tension anchoring device and the centroid of the compression boundary members. However, some newer systems have been developed with lighter residential construction in mind. Check out our deck … endobj We’ve been a family-owned and operated company, serving the needs of the concrete construction industry, since 1926. Similar force modifications for wind demands do not apply. WHO WE ARE TROY NIBBELINK President/CEO Nibbelink is a family owned business, and we have always considered our staff to be a part of that family. Comments posted to STRUCTURE website do not constitute endorsement by NCSEA, CASE, SEI, C3 Ink, or the Editorial Board. Because the International Building Code (IBC) treats podium … Recognized, comprehensive guidelines and design examples providing in-depth coverage are available, demonstrating traditional methods of analyzing mid-rise and podium designs.▪, International Building Code. We partner with developers and architects that run the gamut in terms of experience - from seasoned post-tensioned concrete podium … These elements are Columns, Walls, beams, and decks. Traditional methods of calculating wall deflection using the three- or four-part deflection equation do not account for multi-story shear wall effects on structures having more than three stories. … x��}�SS��$�� Concrete is taken off by the four elements that make up the structure. For buildings designed in jurisdictions enforcing codes preceding the 2015 IBC, this would require an alternate means and methods request approval by the Authority Having Jurisdiction (AHJ). Figure 1. Where the aspect ratio is greater than 2:1, the nominal shear capacity must be adjusted to account for the reduced unit shear capacity in high aspect ratio walls due to the loss of stiffness as the aspect ratio increases. 5 0 obj High Performance Solution. If a rigid diaphragm analysis is warranted, the transverse walls would also act to resist torsional forces. And, although concrete is inherently durable, leaving it unprotected is an invitation for premature deterioration. The amplification factor in ASCE 7-10 Section 12.2.3.2 (d), when used, applies to only the seismic component of the reaction forces, not the entire reaction-included gravity loads. 2012. Structurally, ASCE 7-10 Section 12.2.3.2 provides a two-stage analysis procedure that can be beneficial for seismic design of podium projects. ��< Ȕ��Ip m�vn[m��3&�n'eL 4��L�H��֫z��}�իW�x��V��o��{�k��|jW*b��^{ |��g ! Rooftop and podium concrete decks are used for car parks, equipment plants, and similar situations. 6 0 obj b) The period of the entire structure is not more than 1.1 times the period of the upper portion considered as a separate structure supported at the transition from the upper to lower portions. 0 INTRODUCTION 1 DESIGN CONSIDERATIONS. However, knowing that this allowance is provided in the 2015 edition often eliminates the AHJ’s concerns. %�� Typically, they are exposed to all extremes of the weather. Fig.2: Podium slab; precast hollow core units used for construction. A watertight roof performs a vital function in protecting employees, visitors and physical assets. All images courtesy RJC Engineers. <> ASCE 7-10 Section 12.3.1.1 (c) allows diaphragms in light-frame structures to be idealized as flexible when 1½ inches or less of non-structural topping, such as concrete or a similar material, is placed over WSP diaphragms, and each line of vertical elements of the SFRS complies with the allowable story drift of ASCE 7-10 Table 12.12-1. “Recent years have seen an increase in the use of podium decks, and it has been recognised that there has been a significant increase in failures. We offer our construction expertise in the Northwest and Rocky Mountain regions. Typically, they are exposed to all extremes of the weather. Podium designs are one way to maximize the number of stories, increase unit density, and lower construction costs. The last term accounts for rigid wall rotation. The St. Teresa’s of Calcutta affordable housing project topped out on the corner of 14th & Commercial in downtown San Diego this month. Podium structures have become common in the United States as the demand has increased for dense, mixed use spaces and multi-unit residences. Contact publisher for all permission requests. Common configurations include up to five stories of residential use over retail, commercial, office, and parking occupancies, similar in configuration to the building shown in Figure 1. Multi-Family Podium Construction Fact Sheet. As we’ve mentioned elsewhere, the culprit for premature deterioration is moisture. Traditional shear walls must comply with the allowable height-to-width, (h/b), aspect ratios of the 2015 SDPWS, which can be found in Section 4.3.4 and Table 4.3.4. 12 0 obj This can significantly affect multi-story shear wall stiffness and capacity. <> (For all other building requirements this is still one building because two residential stru ctures are interconnected by a common parking garage. <> <> These materials use the following take off units in an estimate: Rebar - pounds or tons <> �C[�>|l��;z��sC��C��>� Reinforced concrete floor decks have become increasingly popular in homes over the last decade, and many of the floor systems used are adapted from commercial construction. Table 12.6-1 of ASCE 7 only allows equivalent lateral force for certain characteristic. It engages, enlightens, and empowers structural engineers through interesting, informative, and inspirational content. Unless a diaphragm can be idealized as either flexible or rigid in accordance with Sections 12.3.1.1, 12.3.1.2 or 12.3.1.3, the structural analysis shall explicitly include consideration of the stiffness of the diaphragm (i.e. podium. Generally, this type of slab constructed and placed at gro… Podium designs are one way to maximize the number of stories, increase unit density, and lower construction costs. Varying rod diameters help reduce rod elongation and wall rotation and produce a more efficient and cost-effective system. In multifamily residential structures, a concrete Podium Slab typically acts as both a structural floor and as a transfer slab for wood and light gauge steel framed construction above. Currently, some designers only perform a flexible diaphragm analysis and some a rigid diaphragm analysis, but a few use semi-rigid modeling (enveloping). Even though diaphragms may be idealized as flexible, it is sometimes good engineering judgment to consider other flexibility conditions. If the deck is reinforced concrete, use reinforced, minimum 215 mil thick hot fluid-applied rubberized asphalt, applied directly to the deck, in a protected membrane roof assembly (PMR) often referred to … The other option is to use platform framing, which is easier to install, reduces stud heights, takes less time to install, and can eliminate the joist hanger and costs associated with semi-balloon framing. The sum of the lateral forces from the walls above is transferred to the walls below as shown in Figure 5. For SDPWS Equation 4.3-1, the first term represents the bending deflection resulting from the lateral forces applied at the top of the wall. However, the 2015 IBC allows multiple story podiums. Learn More. beam, post-tensioned slabs, columns) supporting a discontinuous shear wall is designed for over-strength where required by ASCE 7-10 Section 12.3.3.3. We will teach you how to determine the code compliant size of your footings based on the soil type and tributary loads. semi-rigid modeling assumption). 3 PODIUM AND / OR PARKING ROOF DECKS COMBINED .