SAFStor Multi-Story Self Storage

In the world of climate-controlled, multi-story, self storage, SAFStor is leading the way with new developments underway across the country. With ambitious expansion goals and tight construction schedules, SAFStor selected ARCO Design/Build  to lead the development process as the design/build contractor. Based on our experience with both self storage and cold-formed steel design, Dudley Engineering was selected based on qualifications to provide the structural engineering for these developments. 

Multi-Level Self Storage

Multi-level self storage is a relatively new development in the world of self storage that is gaining steam particularly in densely populated areas. From a structural perspective, multi-level self storage facilities require a much more in-depth analysis of load paths and material behavior when compared to conventional single-story self storage facilities.

Modern single-story self storage facilities typically fall within the wheelhouse of metal building companies and are constructed out of cold-formed zee and cee members with metal panel for the walls and roof.  Our scope on these projects is typically limited to providing the foundation design and reviewing the metal building submittal to confirm whether it is in general conformance with the building code.

Conversely, multi-story self storages facilities generally necessitate full-service structural engineering firms such as Dudley Engineering to design both the foundation and superstructure.

Reasons to involve a full-service structural firm include:

  • Complicated load paths stemming from:
    • Office/Public space on the 1st Level which require transferring the load bearing walls above.
    • Unit configurations varying from level to level.
  • Multiple materials utilized in the construction that are required to behave amicably. For example, a large portion of lateral resistance of the structure is typically derived from the stair and elevator shaft walls which are usually constructed out of concrete masonry units (CMU). Conversely, the primary gravity load resisting components are cold-formed steel stud walls.
  • Integration of ancillary components such as canopies, awning and parapets that are typically outside the expertise of metal building companies.

Below is an image of the SAFStor project in South Houston along with some example of the framing used.

To learn more about this project, the design-build process or the framing system contract Bryan Tyson, PE (Project Manager and Engineer-of-Record) at btyson@dudleyengineering.com or Drew Dudley, PE (Principal-in-Charge) at ddudley@dudleyengineering.com.

SAFStor Old Spanish Trail - Multi-Story Self Storage
SAFStor Old Spanish Trail – Image from ARCO Design/Build & ADB Design Services

 

Typical Self-Storage Cold-Formed Steel Framing
Typical Self-Storage Cold-Formed Steel Framing
Typical Composite Steel Deck on Stud Wall Framing
Typical Composite Steel Deck on Stud Wall Framing

Park View at Oak Forest – Townhome Development

Townhome Location:

West 34 1/2 Street, Houston, Texas near Oak Forest

Townhome Architecture:

This development consists of (25) individual townhomes each consisting of a three-story unit of approximately 3,000 square feet. There are (4) unique models with each model having floor plan and elevation options to allow customization. For a full description of the option visit the architect (Moment Architects) page, link below.

https://www.moment-architects.com/projects/

Townhome Rendering_Claire Option
Townhome Rendering_Claire Option
Townhome Rendering_Bennett Option
Townhome Rendering_Bennett Option

Townhome Structure

The structural consists of a post-tensioned stiffened slab-on-ground foundation with conventional 2×6 (exterior) and 2×4 (interior) wall framing, wood floor trusses and then a mix of wood roof trusses and conventional braced rafter roof construction.

Structural OSB sheathing was used for the shear walls with Simpson Strong-Tie holdowns.

To resist the high wind speeds prevalent in Houston, we utilized Simpson Strong-Tie hurricane clips and straps to form a complete load path.

Townhome Structural Framing
Townhome Structural Framing

Learn more about our multi-family experience:

Vist our Service page: https://dudleyengineering.com/multi-family-construction/

 

 

 

 

 

 

 

 

 

 

C-Store Design

C-Store Design:  A Blend of Structural Steel and CMU Construction

C-Store Structure:

Foundation

The type of foundation utilized for C-Stores is dependent upon the results of the site-specific geotechnical report, however due to the light loading from the superstructure the foundation will not necessitate deep foundations (drilled piers, auger cast piles, etc.). For foundations on non-expansive soil, continuous spread footings with a non-structural slab are commong. For foundations on expansive soils, stiffened slab-on-ground foundations are typically utilized since the controlling loading will be the active soil and not the superstructure loading.

Superstructure:

Typical C-Stores are constructed with CMU (concrete masonry unit) walls and structural steel open-web roof joists. The CMU walls serve as the load bearing element for both gravity loading (dead, live, snow, wind uplift, etc.) and as shear walls for lateral loading (wind, seismic). Open-web steel roof joists are a practical option for the roof framing due to their truss configuration which allows them to span large distances at a relatively low cost. The front of the C-Store is typically framed with structural steel columns and beams due to the large storefront windows that preclude the use of CMU walls.

Fuel Tanks:

Fuel tanks present a special condition for C-Store design as they can become buoyant during flooding events. For example, the self-weight of a 20,000 gallon fuel tank is approximately 10,000 pounds. Assuming that the soil has become saturated and the fuel tank is empty, the buoyant force will be approximately 165,000 pounds. To overcome this buoyant force, deadmen anchors are employed  to provide additional restraint.

 

 

 

 

 

 

 

 

 

 

 

Fuel Canopy

The fuel canopy structure typically consists of HSS (Hollow-Structural Section) steel columns with “carry” wide-flange steel  beams directly above spanning the short dimension of the canopy which then support the “purlin” wide-flange steel beam spanning the short direction. The metal roof deck is fastened to the soffit (bottom) of the steel beams. The HSS columns are typically founded on deep foundation elements.

 

Construction Photos

Beam Pockets for Open-Web Steel Roof Joists

C-Store Owners: Timewise-Landmark, Buc-ee’s, Stripes

Oil Change Facility

Location: Conroe, Texas

Program:

This function of this building will be a service center for automobiles and RV’s including but not limited to oil changes, state inspections and mechanical service. The building is two-stories with the bottom story being a basement (highlighted in yellow below).

Structural System:

Basement (Pit) – Cast-in-place concrete walls with isolated spread footings for the interior columns.

Structural Floor Above Pit : Composite concrete deck with 1½ composite metal deck with 4½” of reinforced concrete for a total thickness of 6″. The composite deck is supported by composite structural steel beams which frame into structural steel columns and the cast-in-place concrete basement walls.

Level 1 Slab: Stiffened slab-on-grade.

Superstructure: Metal Building System.

Unique Design Criteria:

The elevated floor of the pit needed to be designed to support a Class A RV which  based on our research indicated a 26,000 pound total weight. We utilized the AASHTO HS-10 (bridge design) weight distribution formula which assigns 80% of the weight to the rear axle and 20% to the front axle/ This resulted  in a design vehicular wheel load of 10,400 pounds on a minimum contact area of 150 square inches.

Composite Structural Steel Beams:

View our blog about composite construction at the following link: Composite Construction

Project Photos:

  

Fire Damaged Concrete

Structural Diagnostics : Assessing Fire Damage

Foundation Exposed to Intense Fire

Dudley Engineering was engaged to perform a structural assessment of a foundation in Bryan, Texas that has been exposed to an intense fire. The 4-Alarm fire resulted in a complete loss of the superstructure and wisely the owner engaged Dudley Engineering to ascertain whether the foundation was damaged, prior to rebuilding.

Principal, Bryan Tyson, PE led the assessment which consisted of a visual assessment of the foundation including:

  • scorch marks
    • Smoke stains and scorch marks are typically good indicators of areas that were exposed to high heat and require further evaluation (see sounding hammer below)
  • cracks
    • Concrete exposed to high heat and then subsequently doused with water as is typical in a normal structural fire, can lead to drastic temperature changes and hence quick expansion and contraction of concrete leading to cracks. Consider placing a glass in the freezer and then subsequently removing it and running hot water over it, it will crack (not that we have ever done that before).
  • changes in color
    • A change in the color of the concrete may indicate that the concrete was exposed to heat exceeding 550°F. Concrete exposed to temperatures above 550°F often turn a shade of pink which indicates that a chemical change has occurred in the iron-containing aggregates and cement paste.
  • surface spalls
    • High heat can cause the pore water in the concrete to evaporate which can lead to spalling of the concrete.

The assessment also included testing of the concrete via a sounding hammer. A sounding hammer can be used to compare the resonance of the concrete after it is struck by the hammer. Healthy concrete will exhibit a sharp, high-frequency ringing sound when struck, while damaged or poor-quality concrete will typically exhibit a dull thud or soft noise.We, in corroboration with may documented cases, have found the sounding hammer technique to be a reliable and cost-effective means of assessing damage to concrete in the wake of a fire. The sounding hammer can also be used for destructive testing to assess the strength of the concrete. Healthy concrete will be unphased by a couple blows from a sounding hammer while heat-damaged concrete will crumble away with a few rigorous hits. Additionally the fracture mechanics of heat-damaged concrete is unique in that the fracture plane will typically form around the aggregate as opposed to directly through the aggregate, which is characteristic of healthy concrete.

To learn more about Dudley Engineering’s Structural Assessment / Diagnostics capabilities click on the link. 

Chalky Cement Paste – Indicative of Heat-Damaged Concrete
Spalling Concrete with Pink Color Tones – Fracture Plane Around Aggregate Pieces
Pink Color Change of Concrete

Metal Plate Connected Wood Trusses

Metal Plate Connected Wood Trusses – From Design to Fabrication

We were recently invited to go on a tour of Trussworks, LLC plant in Caldwell, Texas. Seeing the fabrication process and speaking with the truss design manager, Timothy McPeck and general manager, Justin Groom was a great learning experience. Blending the metal-plate connected wood trusses into the structural frame can provide an economical and safe solution for any project of Type III or V construction, however it requires the structural engineer-of-record and architect to have a solid understanding of the capabilities and limitations, this tour certainly put Dudley Engineering LLC a step ahead.

We have completed multiple projects with Trussworks and have found them to be a great partner is helping deliver successful projects.

Wood trusses are common in Multi-Family and light Commerical projects. They have the capability to span large distances while still leaving room for MEP which avoids the need for a drop ceiling.

Floor Truss Assembly Line
Roof Truss Assembly Line

Floor Truss Jig

Sway Bee Caves – Thai Cuisine

A Blend of Fine Dining and Innovative Design and Construction

Dudley Engineering blended the cold-formed steel design with the structural steel frame to provide a robust and economical structural system. The structural system consisted of cold-formed steel diagonal strap braced X-bracing lateral system, cold-form steel and structural steel roof joists, cold-form steel roof trusses, and composite structural steel beams with composite metal deck.

The use of cold-formed steel cut down the construction schedule as well as material and labor costs since all the members can be handled by a single laborer and connections can be completed via metal screws in lieu of welding or bolting.

Project Manager: Drew Dudley, PE

Location:

Photos

Example of Structural Drawings

Contact Drew Dudley, PE at ddudley@dudleyengineering.com for more information or to view a full set of the structural plans.

First Baptist Church – Huntsville, Texas

First Baptist Church Family Life Center

Huntsville, Texas

About

Dudley Engineering provided structural engineering and building envelope design, consulting and inspection for this church facility which consisted of structural steel framing, cast-in-place concrete basement walls, cold-formed metal framing stud walls and brick veneer. We enjoyed getting to spend time in Huntsville and especially enjoyed getting to eat at the nearby Farmhouse Cafe (@farmhousecafehuntsvilletx) which never disappoints.

Multi-Family Development | Spring, Texas

Project Description

Dudley Engineering provided the structural engineering design for the foundation and superstructure of this multi-family development in Spring, Texas.

In collaboration with Moment Architects, Dudley Engineering sought to reduce the structure cost by utilizing advanced framing techniques and engineered wood products.As part of our full-service approach, Dudley Engineering also provided construction administration and inspection services to verify construction.

Location

Kuykendahl Road and Gosling Road | Spring, Texas

Additional Information

Read more about our multi-family expertise here: Dudley Engineering Multi-Family Service

 

Advanced Framing Techniques: Successful Utilization


In the pursuit of the infamous structural engineer T.Y. Lin’s powerful statement “To engineers who , rather than blindly following the codes of practice, seek to apply the laws of nature” I have always been interested in the subject of advanced framing techniques. The basic premise of advanced framing techniques is “a system of construction framing techniques designed to optimize building materials to produce wood-framed buildings with lower material and labor costs than conventional framed structures. Builders who utilize advanced framing techniques optimize framing material usage, reduce wood waste and, with effective insulation detailing, boost the building’s efficiency to meet today’s energy code requirements. When properly designed and constructed, advanced framed walls that are fully sheathed with wood structural panels, such as plywood or oriented strand board (OSB), provide the structural strength necessary to safely withstand the forces of nature.” (APA The Engineered Wood Association).

For professionals who have experience in structural steel and reinforced concrete framing systems, the definition of “advanced framing” will sound very similar to what has been the standard practice in steel and concrete for decades. The reason this practice is titled “advanced” in the wood industry is due to the wide use of prescriptive design, which has never been prevalent in the steel and concrete industries. It is my belief that the development of the prescriptive design in the International Residential Code has caused the wood framing industry to largely lag behind its counterparts in terms of material and labor efficiency. With the availability of software programs that can readily analyze wood framed structures I think it is time for the wood industry to re-evaluate the widespread use of prescriptive designs and utilize advanced framing techniques to elevate wood framing up to par with concrete and steel framing techniques.
I recently had the opportunity to put advanced framing techniques to the test with my own personal residence. My wife and I designed our 2,800 SF ranch house on our 10 acre property in Montgomery, Texas. For the framing, I designed all of the exterior walls to be 2×6 studs @ 24” O.C. The material savings came out to approximately 30% compared to traditional 2×4 stud walls @ 16” O.C. Other advanced framing techniques that were utilized included:
floor joists and rafters spaced @ 24” O.C. which took advantage of the the subfloor and roof deck’s inherent ability to span distance greater than 16” and reduced the total number of pieces.
Insulated exterior headers which reduced thermal bridging with little detriment to the structural capacity.
Blocking and straps at shear walls utilizing the “Force Transfer Around Openings” analysis approach that reduced the total length of shear walls required.

In the end, the framer was able to successfully implement the design as intended. Besides the material savings, the advanced framing techniques also provide additional benefits such as a larger cavity space for insulation in the exterior walls and less thermal bridging due to the reduced number of pieces in the exterior wall. I consider this implementation of advanced framing a success and look forward to its use on future projects.