Construction is Underway on the Salesforce Tower

Another of The Conco Companies’ projects, the Transbay Tower was recently renamed the Salesforce Tower after the company leased a large portion of the building to become the biggest commercial real estate deal in San Francisco's history.  The new Salesforce Tower is designed by Cesar Pelli of the Pelli Clarke Pelli Architect firm and will transform the city’s skyline to become the tallest building in San Francisco and the second tallest skyscraper west of the Mississippi.

Here are some interesting facts on the new Salesforce Tower:

·        Once completed, the tower will have 1.4 million sq. ft. of office space and Salesforce will occupy 714,000 sq. ft. of it.

·         Building will be 61 floors, and have a height of 1070 feet (326 meters).

·         Salesforce will occupy the floors 1-30 as well as the whole top floor.

·         A new Transbay Transit Center will be located at the base of the tower.

·        According to the architect, the design of the skyscraper has the simple, timeless form of the obelisk, giving the 60-​story tower a slender, tapering silhouette.

·         The walls are composed of clear glass with pearlescent metal accents. 

·         High performance, low-​emission glass as well as the integrated sun shades on each floor will help to reduce the building’s cooling load.

·         Both the tower and transit center will include water recycling systems.

·         The tower is expected to receive LEED Gold certification.

 

Conco is busy laying the groundwork to accomplish another historic feat this coming fall by undertaking the largest continuous mat pour in San Francisco that will be nearly 14,000 cubic yards.  Like the Wilshire Grand Tower in L.A., both skyscrapers will have a concrete core with a structural steel frame requiring lightweight concrete to be pumped at heights that had not previously been attempted on the West coast.

Sources:

 

http://sf.curbed.com/places/transbay-tower

http://pcparch.com/project/transbay-tower

 

Conco is one of the leading concrete contractors in San Francisco offering a range of innovative, quality services.  We have been honored to work on many high-profile projects and recently completed the extensive concrete work for the San Francisco 49ers Stadium.  We have been offering premium concrete services throughout the Western U.S. since 1959, and have four regional offices serving California, Washington, Oregon, Nevada and Colorado.

 

 

A Short History of Shotcrete

 

Shotcrete is pneumatically placed concrete that is used as an economical alternative to traditional cast-in-place walls.  As it almost eliminates the forming process all together, it greatly reduces labor cost and time.  Shotcrete has the same structural characteristics as traditional cast-in-place walls and a wide range of applications including shear walls, retaining walls, architectural walls, slope pavement, and soil nailing. 

Wikipedia reports that shotcrete, originally known as gunite, was first used to repair the crumbling façade of the Field Columbian Museum in Chicago in 1907 by a well-known naturalist, Dr. Carl E. Akely.  He used a process where dry material was blown out of a hose and water was injected from the nozzle.  Mr. Akeley later went on to patent the equipment, which was called a cement gun, and the material called Gunite.  The Cement Gun Company was soon started (now called Allentown Equipment).

It was not until mid-1950 that a wet mix method was introduced to the construction industry.  Right from the start the benefits were recognized and it was successfully used on many projects.  Shotcrete really took off from there with the development of a rotary gun that had an open hopper, which allowed the material to be continuously fed.    

The American Shotcrete Association credits the technical advancements in materials and equipment made during the 1970’s of providing a huge improvement in the applications of shotcrete.  They report that, “The Engineering Foundation organized the first conference for The Use of Shotcrete for Underground Support.”  Furthermore, they write that, “Perhaps the most significant step in this period was the development of efficient concrete pumps that could be used for wet shotcrete application.”

The 1980’s saw advancements in the mixing and batching of ready mix concrete with developments of admixtures that allowed for consistency, hydration and performance.  One of the biggest changes in the shotcrete that is used today is the ability of equipment to pump any slump and to be able to pump it over long distances and up into high rise construction projects.  

* http://en.wikipedia.org/wiki/Shotcrete

* http://www.shotcrete.us/

* source: American Shotcrete Association

Conco is taking a more active role in the Portland area with our expansion of high-quality commercial concrete services.  We bring our years of experience delivering dependable services since 1959, and a vast portfolio of noteworthy and large-scale projects from throughout the Western U.S.  Our work includes commercial, industrial, educational and multi-residential construction as well as public works projects. 

Opportunities for Hard Working Construction Laborers

By Conco  

The Conco Companies continues to seek experienced carpenters, cement masons, ironworkers, operating engineers as well as job opportunities for construction laborers.  We have openings at all of our locations, which include Northern California, Southern California, Washington State, and Colorado.  These are union positions (with the exception of Colorado) and offer competitive wages along with medical and retirement benefits.

Conco’s openings for construction workers include Bridge Laborers and General Laborers.  The responsibilities include all work in connection with but not limited to: dumpman, load Spotter, flag person and operating a forklift.  We are an equal opportunity employer.

At Conco we employ a dedicated crew of laborers and cement masons who are some of the most experienced in the industry.  We provide crews with the most up-to-date equipment and tools to assist them with optimally performing each job and to continue to meet deadlines.  Additionally, Conco is committed to providing all employees a hazard-free, safe working environment.  

To achieve this goal, our safety program focuses on hazard elimination.  We sincerely believe that when safety is the first consideration before any work begins, everyone wins.  Safety pays for our company, our employees, our customers and the general public!

We are sure you will find our company is an exciting place to work.  We have had the privilege to be a part of many distinguished project throughout the Western U.S.  Recently we provided the concrete services for the San Francisco 49ers Levi Stadium.  Last fall we assisted on the repairs for the new Bay Bridge also in San Francisco.  Our most recent accomplishment was to break the world record for the largest continuous mat pour that was done for the Wilshire Grand Center in Los Angeles.
 

If you are interested in applying for a position, please refer to our website for more information.  

Conco is a leading supplier of concrete services for the Western United States. We have built our reputation with superior concrete formwork, reinforcing, place and finish, shotcrete and other ancillary services that benefit from our vast experience. With state-of-the-art equipment and modern facilities, we work diligently to meet goals and stay within budget.

Post Tension Cable

Conco is now one of the largest reinforcing steel and post tension cable suppliers in the Western U.S.  Our high-quality post tension (PT) cable meets precise engineering specifications and provides a great value to customers throughout Northern California, Southern California, Washington, Oregon and Colorado.  So what is post tensioning and how is it used in concrete construction?  

Post tensioning is the process of using high-strength, prestressed steel cables or tendons to actively reinforce concrete and apply compression after concrete is poured.  Once the concrete has hardened, the cables are tensioned, or pulled tight with hydraulic jacks and anchored to the outside edges of the concrete.  Pre-tensioned concrete, according to Wikipedia, “is cast around steel tendons—cables or bars—while they are under tension. The concrete bond to the tendons as it cures, and when the tension is released it is transferred to the concrete as compression by static friction.” 

The job of fabricating, assembling, and installing PT cable requires highly skilled workers and specialized tools.  Post tensioned concrete has all the same attributes of reinforced concrete but is used in projects that call for thinner slabs or when a greater span length is called for between support columns.  Many projects could not be done without the use of post tensioning, and it is often the choice for parking structures as it allows flexibility in the design of ramps and span lengths.  The system is also commonly used in stadiums, bridges, and office and apartment buildings.  

Additionally post tensioning reduces the amount of beams needed and allows beams to be placed the full length of a structure rather than from column to column.  Since slabs and other structural members can be constructed thinner, they require less concrete, and thereby, reduce the overall weight of a structure.  It also reduces or eliminates shrinkage cracking and is considered to be active reinforcement.    

* http://en.wikipedia.org/wiki/Prestressed_concrete 

*http://www.dsicanada.ca/uploads/media/DSI-USA_What_is_Post-Tensioning_us_02.pdf

For over 50 years, Conco has been providing premium concrete services and is one of the most trusted concrete contractors in Seattle.  We partner with clients on every project from the pre-construction stage right through to final completion to maximize efficiency and ensure goals and budgets are met.  Our concrete services include commercial, educational, parking and other construction development as well as public works projects.

Helping to Build the CityCenter in Las Vegas

A few years ago Conco provided concrete services for the CityCenter’s residential towers that are located on the Las Vegas Strip in Paradise, Nevada.  The CityCenter is a 16,797,000 square foot, mixed-used complex that consists of hotels, residential housing, high-end retail, a casino, entertainment venues and a variety of fine dining.  The complex opened in December, 2009. 

Developers on the project were MGM Resort International and Dubai World, and the total cost of the project is estimated to be $9.2 billion.  The contractor was the Perini Building Company.  The massive project includes the Aria Resort and Casino, The Shops at Crystals (an ultra, upscale retail mall), the Mandarin Oriental, a luxurious hotel with an Asian theme, the Vdara Hotel and Spa, and the Veer Towers, a premier residential development.  The CityCenter also includes a 6,900 car parking garage and a Clark County Fire Station. 

The Veer Towers are two 37-story glass towers with 335 residences located above The Shops at Crystals.  The internationally renowned Chicago architect, Murphy/Jahn Architects, designed the towers that are inclined at five-degree angles, and thus aptly named.  The beautiful, spacious lobby contains monumental glass boxes that are flooded with light, and exposed concrete walls that are filled with an impressive collection of modern artwork.  

The modern building offers studios, deluxe studios as well as luxurious ones, two and three bedroom flats and penthouses.  The sizes for the residential units range from 500 to 3,300 square feet.  At the top of each stylish tower there is an amenities and recreation floor that offers panoramic views of Las Vegas and is equipped with an infinity edge pool, sun deck, patio, and fitness center.  The Veer Towers opened in July, 2010.

Conco is a leading supplier of concrete services for the Western United States.  We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products. Our concrete services include commercial, educational, parking and other construction development as well as public works projects.

Cast-in-place Concrete

By Conco  

Cast-in-place concrete is a commonly used building material for commercial and residential structures and accounts for 75% of all concrete used.  The process starts with a temporary form in which reinforcement such as steel bars (rebar) may be added.  The next step is to pour the liquid, ready mix concrete that has been transported to the jobsite (it may in some cases be mixed on site) into the removable forms.

Using cast-in-place offers the same benefits as other types of concrete such as durability, and strength and can use some recycled material.  It is resilient when faced with severe weather conditions such as tornados as well as resistant to mold, rot, bugs, and fire.  The thermal mass of the concrete helps to reduce a building’s energy costs and has the added benefit of acting as a sound insulator.  Moreover the concrete is ready to use once the forms are stripped and does not require any further treatment.

Originally this method was only used for sub-grade walls but the renowned inventor, Thomas Edison, experimented with using cast-in-place concrete on above-grade projects.  He demonstrated the success of his work by constructing several homes that were made entirely out of cast-in-place concrete.  With many improvements and new developments since then, cast-in-place is now used for constructing slabs, walls, beams columns floors, and roofs as well as for forming special architectural features.

The forms need to remain in place until the concrete is self-supporting.  Since one of the primary costs of cast-in-place is the forming process, using prefabricated formwork can help speed up a job and save money.  They are assembled on site and can be reused over and over again.

Conco is a leading supplier of concrete services for the Western United States. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products.  Since that time, we have steadily taken a leading role as one of the Bay Area’s top concrete contractors. 

Chemical Admixtures in Concrete

Chemical admixtures are natural or manufactured chemicals that are added to concrete along with portland cement, aggregate, and water.  They can be a liquid or powder and are added to the concrete immediately before or during the mixing process.  The chemical admixtures in a mix will account for less than 5% of the total concrete.   

The purpose of chemical admixtures is to give the concrete additional properties to handle circumstances such as pumping requirements or when placing concrete during extreme weather conditions.   According to the Portland Cement Association, “Admixtures are classed according to function. There are five distinct classes of chemical admixtures: air-entraining, water-reducing, retarding, accelerating, and plasticizers (superplasticizers).”

The National Ready Mix Concrete Association (NRMCA) says that the most common chemical admixtures used are air-entraining agents, water-reducers, and water-reducing retarders and accelerators.  They state that admixtures are added to concrete to increase “durability workability or strength characteristics of a given concrete mixture.”

Accelerators are used to increase the early strength of concrete by causing it to harden quicker and are used to protect concrete from extreme cold or when there is a tight project deadline.  Chemical accelerators are chloride based or non-chloride based and calcium chloride is one type commonly used as it is inexpensive.

Retardants are used to slow down or delay the hardening process such as in situations where the job demands a slower pour due to the scope of the project or when in very hot temperatures.  It provides a crew additional time to place and finish the concrete.   Common retardants are lignin, sugars, and citric and tartaric acids.

Air-entraining is the process of deliberately adding microscopic air bubbles into the concrete.  The purpose of doing this is to increase the concrete’s durability when faced with cycles of freezing and thawing conditions and to improve the concrete’s workability.    Furthermore segregation and bleeding is diminished or completely eliminated.  The only negative is that the concrete experiences a 5% reduction in strength for each 1% of air added.

1. http://www.cement.org/cement-concrete-basics/concrete-materials/admixtures
2. http://www.nrmca.org/aboutconcrete/cips/15p.pdf

Conco is one of the leading concrete contractors in San Francisco offering a range of innovative, quality services.  We have been honored to work on many high-profile projects and were recently awarded the concrete package for the San Francisco 49ers Stadium.  Our concrete services include commercial, educational, parking and other construction development as well as public works projects.