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Structural Engineering

Our latest structural engineering projects and advice.

Focus on Mass Timber – Green Drinks

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Our President and senior structural engineer will be presenting with industry experts on Mass Timber and modern wood construction.  Our focus will be on our expertise and experience with the resurgence of modern timber framing in residential and commercial projects.

Timber framing was the original mass timber construction type that was used for centuries until steel and concrete took over. Now with engineered wood products our built environment is returning to mass timber construction.

Be sure to join us on August 13!

Sign Up Here

Retaining Wall and Deck Design

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For this project we designed a new retaining wall to replace an existing failed retaining wall. The house and deck has an overlooking view of the St. Lawrence River near Brockville, ON. Part of the design was to ensure the structure was aesthetically pleasing to compliment the views and atmosphere.

The new retaining wall features buttresses for support and a new poured concrete retaining wall. The wall will be clad in an architectural stone for a more natural look.

 

 

Our office is located in Brockville, Ontario. We can assist you with your upcoming renovation of your deck, patio or landscaping. Our designs come 3D modeled for better visualization and constructibility. From the 3D model we will create permit and construction drawings to get your project to the next step.

A retaining wall and deck design
A retaining wall and deck design located on the St. Lawrence River near Brockville, ON.

Do I Need Construction Inspections?

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Required Inspections

Throughout the course of construction the Ontario Building code requires construction inspections by a Professional Engineer and/or an Architect. The requirements of these inspections depend on the use, occupancy and size of the building. These inspections ensure that construction is proceeding according to the design. Furthermore, Ontario Regulation 260/08 Performance Standards under the Professional Engineer’s Act reinforces the need for general inspections during construction.

Ontario Regulation 260/08, Part 1

(2) The following are prescribed as performance standards with respect to the general review of the construction of a building by a professional engineer as provided for in the building code:
1. The professional engineer, with respect to the matters that are governed by the building code, shall,
i. make periodic visits to the construction site to determine, on a rational sampling basis, whether the work is in general conformity with the plans and specifications for the building,
ii. record deficiencies found during site visits and provide the client, the contractor and the owner with written reports of the deficiencies and the actions that must be taken to rectify the deficiencies,
iii. review the reports of independent inspection and testing companies called for in the plans and specifications and which pertain directly to the work being reviewed,
iv. interpret plans and specifications in writing when requested to do so by the client, the contractor or the owner, and
v. review shop drawings and samples submitted by the contractor for consistency with the intent of the plans and specifications.

Ontario Building Code Section 1.1. Administration

1.1.1. Administration

1.1.1.1. Conformance with Administrative Requirements

(1) This Code shall be administered in conformance with the Act.

Section 1.2. Design and General Review

1.2.1. Design

1.2.1.1. Application

(1) Article 1.2.1.2. applies with respect to a building described in clause 11 (3) (a) or (b) of the Architects Act or subsection 12 (4) or clause 12 (5) (a) of the Professional Engineers Act.

1.2.1.2. Design by Architect or Professional Engineer

(1) Where the foundations of a building are to be constructed below the level of the footings of an adjacent building and within the angle of repose of the soil, as drawn from the bottom of the footings, the foundations shall be designed by a professional engineer.
(2) A sprinkler protected glazed wall assembly described in Article 3.1.8.18. of Division B shall be designed by a professional engineer.
(3) A shelf and rack storage system described in Section 3.16. of Division B shall be designed by a professional engineer.
(4) The time-based egress analysis for a shelf and rack storage system described in Sentence 3.16.1.7.(7) of Division B shall be prepared or provided by an architect or a professional engineer or a combination of both.
(5) The supporting framing structure and anchorage system for a tent occupying an area greater than 225 m² shall be designed by a professional engineer.
(6) A sign structure attached in any manner to a building shall be designed by an architect or a professional engineer or a combination of both where it is,

(a) a projecting sign that weighs more than 115 kg, or

(b) a roof sign that has any face that is more than 10 m².

(7) A projecting sign attached in any manner to a parapet wall shall be designed by an architect or a professional engineer or a combination of both.

1.2.2. General Review

1.2.2.1. General Review by Architect or Professional Engineer

(1) The construction, including, for greater certainty, enlargement or alteration, of every building or part of it described in Table 1.2.2.1. shall be reviewed by an architect or a professional engineer or a combination of both as set out in Column 3 of the Table.

TABLE 1.2.2.1.(4)
GENERAL REVIEW

Forming Part of Sentence 1.2.2.1.(1)
Item Column 1 Column 2 Column 3
▼ Building Classification by Major Occupancy(5) Building Description General Review by:
1. Assembly occupancy only Every building Architect and professional engineer(1)
2. Assembly occupancy and any other major occupancy except industrial Every building Architect and professional engineer(1)
3. Care, care and treatment or detention occupancy only Every building Architect and professional engineer(1)
4. Care, care and treatment or detention occupancy and any other major occupancyexcept industrial Every building Architect and professional engineer(1)
5. Residential occupancy only other than retirement homes Every building that exceeds 3 storeys in building height Architect and professional engineer(1)
Every building that exceeds 600 m² in gross area and that contains a residential occupancy other than a dwelling unit or dwelling units Architect(2)
6. Residential occupancy only other than retirement homes Every building that exceeds 600 m² in gross area and contains a dwelling unit above another dwelling unit Architect(2)
Every building that exceeds 600 m² in building area, contains 3 or more dwelling units and has no dwelling unit above another dwelling unit Architect(2)
7. Residential occupancy other than retirement homes and any other major occupancyexcept assembly, care, care and treatment, detention or industrial occupancy Every building that exceeds 600 m² in gross area or 3 storeys in building height Architect and professional engineer(1)
7.1 Retirement home only Every building Architect and professional engineer(1)
7.2 Retirement home and any major occupancy except industrial Every building Architect and professional engineer(1)
8. Business and personal services occupancy only Every building that exceeds 600 m² in gross area or 3 storeys in building height Architect and professional engineer(1)
9. Business and personal services occupancy and any other major occupancy except assembly, care, care and treatment, detention or industrial occupancy Every building that exceeds 600 m² in gross area or 3 storeys in building height Architectandprofessional engineer(1)
10. Mercantile occupancy only Every building that exceeds 600 m² in gross area or 3 storeys in building height Architectandprofessional engineer(1)
11. Mercantile occupancy and any other major occupancy except assembly, care, care and treatment, detention or industrial occupancy Every building that exceeds 600 m² in gross area or 3 storeys in building height Architect and professional engineer(1)
12. Industrial occupancy only and where there are no subsidiary occupancies Every building that exceeds 600 m² in gross area or 3 storeys in building height Architect or professional engineer(3)
13. Industrial occupancy and one or more other major occupancies where the portion of the area occupied by one of the other major or subsidiary occupancies exceeds 600 m² The non-industrial portion of every building Architectandprofessional engineer(1)
The industrial portion of every building Architectorprofessional engineer(3)
14. Industrial occupancy and one or more other major occupancies where no portion of the area occupied by one of the other major or subsidiary occupancies exceeds 600 m² Every building that exceeds 600 m² in gross area or 3 storeys in building height Architect or professional engineer(3)

Notes to Table 1.2.2.1.:

(1) An architect shall provide general review services within the practice of architecture and a professional engineer shall provide general review services within the practice of professional engineering.

(2) An architect may engage a professional engineer to provide general review services within the practice of professional engineering.

(3) Only a professional engineer may provide general review services within the practice of professional engineering.

(4) Requirements for general review by an architect or a professional engineer or a combination of both for the construction, including, for greater certainty, enlargement or alteration, of a building are set out in the Architects Act and the Professional Engineers Act.

 (5) For purposes of Table 1.2.2.1., a retirement home is deemed to be a separate major occupancy.

(2) A person who intends to construct or have constructed a building or part of it required by Sentences (1) and (4) to (9) to be reviewed by an architect or a professional engineer or a combination of both, shall ensure that an architect, professional engineer or both are retained to undertake the general review of the construction of the building in accordance with the performance standards of the Ontario Association of Architects or the Association of Professional Engineers of Ontario, as applicable, to determine whether the construction is in general conformity with the plans, sketches, drawings, graphic representations, specifications and other documents that form the basis for the issuance of a permit under section 8 of the Act or any changes to it authorized by the chief building official.
(3) The architect, professional engineer or both who have been retained to undertake the general review of the construction of a building, shall forward copies of written reports arising out of the general review to the chief building official or registered code agency, as the case may be.
(4) Where the foundations of a building are to be constructed below the level of the footings of an adjacent building and within the angle of repose of the soil, as drawn from the bottom of the footings, the construction of the foundations shall be reviewed by a professional engineer.
(5) The construction of a sprinkler protected glazed wall assembly described in Article 3.1.8.18. of Division B shall be reviewed by a professional engineer.
(6) The construction of a shelf and rack storage system described in Section 3.16. of Division B shall be reviewed by a professional engineer.
(7) The construction of a supporting framing structure and anchorage system for a tent occupying an area greater than 225 m² shall be reviewed by a professional engineer.
(8) The construction of a sign structure shall be reviewed by an architect or a professional engineer or a combination of both, where the sign is,

(a) a ground sign that exceeds 7.5 m in height above the adjacent finished ground,

(b) a projecting sign that weighs more than 115 kg, or

(c) a roof sign that has any face that is more than 10 m².

(9) The construction of a projecting sign attached in any manner to a parapet wall shall be reviewed by an architect, professional engineer or a combination of both.

1.2.2.2. Restriction for General Review

(1) Only an architect may carry out or provide the general review of the construction of a building,

(a) that is constructed in accordance with a design prepared or provided by an architect, or

(b) in relation to services that are provided by an architect in connection with the design in accordance with which the building is constructed.

(2) Only a professional engineer may carry out or provide the general review of the construction of a building,

(a) that is constructed in accordance with a design prepared or provided by a professional engineer, or

(b) in relation to services that are provided by a professional engineer in connection with the design in accordance with which the building is constructed.

1.2.2.3. Demolition of a Building

(1) The applicant for a permit respecting the demolition of a building shall retain a professional engineer to undertake the general review of the project during demolition, where,

(a) the building exceeds 3 storeys in building height or 600 m² in building area,

(b) the building structure includes pre-tensioned or post-tensioned members,

(c) it is proposed that the demolition will extend below the level of the footings of any adjacent building and occur within the angle of repose of the soil, as drawn from the bottom of such footings, or

(d) explosives or a laser are to be used during the course of demolition.

Reducing Greenhouse Gases in the Engineering Industry

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Recently the Ontario Provincial Government announced they are making cuts to the Environmental Commissioner of Ontario’s office and has also produced a less than enthusiastic environmental policy. Silencing the environmental critic isn’t going to change the fact that we have to do something about Climate Change.
Since the Ontario government isn’t going to take responsibility for our environment it falls on our businesses to take up the challenge.

That got us thinking, what can engineers do to reduce green house gases, especially in the construction industry?

Our office at IN Engineering has adopted a substantive environmental policy. We offer engineering services that are completely paperless including drafting and plans, invoicing and reporting. We also use Google servers for all of our file hosting that means our data is stored in the most efficient way possible (compared to local office servers that require a lot of energy). However, as an engineer we have the ability to specify products and materials that lean towards reduced green houses gases.
For demonstrative purposes we designed a beam for a residential property. The beam is supporting a roof and is subject to snow, weight and a maintenance person load. The length of the beam is 10 feet and it supports a tributary width of 10 feet.

Concrete Beam

The first beam designed was a concrete beam. In order to support the loads the beam has to be 8″ deep x 6″ wide with 2 – 20M bars at the bottom for tension reinforcing. It also requires 10M stirrups at 12″ for shear reinforcing. This design is at 98% capacity in bending resistance. The CO2 emissions for cement was researched to be 410 kg per cubic metre [1]. The reinforcing steel in the concrete 0.762 kg of CO2 per kg of steel, 50% of the steel was assumed to be recycled.

The carbon footprint of the concrete beam was estimated to be about 343kg.

Concrete is responsible for about 5% of CO2 emissions worldwide, this is predominately due to the fact that it takes a lot of energy and burning to produce cement. Concrete also requires quarries to produce aggregates and sand which destroy the natural environment. Even worldwide availability of construction sand is becoming an issue – only beach sand is appropriate for concrete as river sand is too smooth.

Steel Beam

The second beam designed is a steel beam. To support the loads, a W5x16 beam was selected with a maximum capacity of 61% in deflection. The CO2 emissions for steel were estimated at 0.762 kg of CO2 per kg of steel and 50% recycled.

The carbon footprint of the steel beam was estimated to be about 28kg.

Wood Beam

The last beam designed was a built up wood beam made of 3-2×12’s and Spruce-Pine-Fir No.1/2. The beam is at 99% capacity in bending. Wood actually sequesters carbon dioxide at about 1.7 kg of CO2 per kg of wood [3]. This means the wood beam actually has a negative carbon footprint.

The carbon footprint of the wood beam was estimated to be about -3400kg (stored).

There are actually more environmental benefits for using sustainable wood products. Forests will sequester carbon as they grow and mature to harvesting. At the end of the life of a wood product it can go to a landfill where it will decompose and produce methane. If the methane is collected then the environmental efficiency of wood increases. Wood is also a light building material, meaning it takes less effort to ship to site and construct.

Conclusion

This is a simple demonstration of how engineers can influence green house gas emissions in the construction industry. A more detailed study on the benefits of wood products was completed by Sathre, R. And J. O’Connor. 2010. A Synthesis of Research on Wood Products and Greenhouse Gas Impacts, 2nd Edition. Vancouver, B.C. FPInnovations. 117 p. (Technical Report TR-19-R)
At IN Engineering we believe that we are responsible for Climate Change and a sustainable future. In our designs we will always prefer to use wood products when the situation allows. We believe that engineered wood products are the future of construction as we enter into a post-industrial era to an environmental renaissance.
 

[1] Environmental Impact of Concrete, https://en.wikipedia.org/wiki/Environmental_impact_of_concrete
[2] Carbon Footpring os Steel, http://www.newsteelconstruction.com/wp/the-carbon-footprint-of-steel/
[3] Canadian Wood Council - Carbon Calculator, http://cwc.ca/carboncalculator/

Retaining Walls

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Retaining walls are structures that hold back earth, most retaining walls over 1 meter or 3 feet in height is a designated structure in the Ontario Building Code (and the National Building Code of Canada).

OBC Clause 1.1.2.2
(2) Subject to Articles 1.1.2.6. and 1.3.1.2., Part 4 of Division B applies to,
       (c) a retaining wall exceeding 1 000 mm in exposed height adjacent to,
               (i) public property,
               (ii) access to a building, or
               (iii) private property to which the public is admitted.

This clause means that most retaining walls have to be designed to Part 4 of the Ontario Building Code by a qualified engineer. A retaining wall would also require a geotechnical investigation by a qualified engineer. Replacing a retaining wall will require multiple engineers and can be a significant task. Furthermore, since retaining walls are generally constructed near property lines a detailed cadastral/land survey may also be required.

There are many options for retaining wall construction and factors such as weight of the retained soil and weight of any vehicles above will govern the design.. Gravity retaining walls rely on their weight to hold back soil, most of the time theres are large concrete walls or cyclopean stone masonry. Retaining walls get a little more efficient when you design a reinforced concrete wall to hold back soil.

There are also pre-cast concrete blocks that are light weight and easy to install. The blocks assemble similar to lego and use a combination of tie backs and their weight to retain soils. The blocks can be cast to look like stone.

At IN Engineering our preferred option when it comes to retaining walls are pre-cast concrete block walls. They are quick and easy to install (saving the owner money) and they are also aesthetically pleasing. The design of these structures is also relatively simple. Lastly, with multiple suppliers in the area these walls are supporting local companies.

Concrete and Cold Weather

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When the air temperature is forecasted to fall below 5 degrees Celsius within 24 hours of placing concrete then special considerations apply for concrete construction. These clauses are in section 7.1.2 of CSA A23.1/A23.2, Canadian Standard for Concrete Materials and Methods of Construction.

If the forecasted temperature is suspected to drop below 5 degrees celsisus (41F) then protection is required. All snow and ice has to be removed from the forms and surface. De-icing salts cannot be used to de-ice the forms. Adequate protection has to be provided to keep the concrete at a minimum of 10 degrees celsius (50F) for the duration of curing, which is typically 3 days. Protection can be heated enclosures, coverings, insulation or any combination of these. Another consideration is that the granular base needs to be preheated before pouring concrete. These prevents such deficiencies as blisters during troweling and delaminations. Using a concrete curing accelerant can also prevent these deficiencies.
Corners, edges and thin sections of concrete are the most vulnerable locations in cold weather and need more protection than plane surfaces. Once the compressive strength reaches 7 MPa it will have sufficient strength to resist frost damage.
Protection should remain in place until the concrete has cooled to the right temperature. This will prevent cracking due to a sudden temperature change.

Heated Enclosures

The enclosures should be constructed to withstand snow and ice build up and being mostly air-tight. The enclosure should have enough space to allow air to circulate over the concrete. Heat can be provided by forced hot air, stationary heaters, hydronic heaters or other approved types. The concrete surface should be protected from any exhaust from the heaters. Carbon Dioxide from direct fire heaters can negatively effect the curing of the concrete.

Protective Covers and Insulation

The cover and insulation should be determined based on the expected temperature differential and wind chill factor. Other factors would include the size and shape of the structure and the amount of cement in the concrete mix.

CSA Standard

Additional information can be found in CSA A23.1/A23.2 and is available to be order on their website. Additional information on cold weather concrete can be found in the American Concrete Institute Standard ACI 306R.

Structural Damage from Ottawa Tornadoes

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Part of our mission statement is to help and support the community. IN Engineering was contacted by Arbuckle Construction Ltd. to perform structural inspections on damaged properties in the Arlington Woods Area of Nepean. Arbuckle Construction assisted with tarping and reinforcing damaged roofs immediately following the storm to prevent further damage from rainwater. Now they are moving on to helping their nieghbours rebuild.
The damage to this area was mostly caused by large trees coming down during the tornadoes on September 21, 2018. Damage to houses was in the upper levels and roofs of the trusses. A lot of trusses are broken and most roofs are going to require a complete replacement.

After performing our inspections of the properties it is amazing that no one was hurt. It’s also amazing to see an entire neighbourhood be stripped of all their trees. Arlington woods once prided itself in having large trees and a canopy over the subdivision.
The damage will be repaired and the trees will grow back. The important part is that everyone is safe and reconstruction efforts are underway.

Coal Shoal Lighthouse Reconstruction

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We are very excited to be able to provide professional engineering services for the reconstruction of the Coal Shoal Lighthouse.
IN Engineering is currently working with the committee working to rebuild the lighthouse after the existing structure built in 1856 burnt down in the Summer of 2018.

Our first step is to reconstruct the original dimensions from any available data – which turns out isn’t that much. All that remains of the original structure is the foundation. We have some data of the original base dimensions of the lighthouse but no original construction drawings. By using Sketchup’s photo match tool we were able to determine that the height based on the dimensions of the base. The height of the original lighthouse was 19ft.

The next steps will be to design the new structure.

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