Constructing Today’s Skyscrapers Require the Use of Tower Cranes

Tower cranes are essential to constructing the extremely tall skyscrapers being built today such as the Wilshire Grand Center in Los Angeles.  Capable of lifting very heavy loads of steel, concrete, generators and other building materials, tower cranes can be erected taller and taller as the building moves skyward.  Wikipedia cites the typical maximum unsupported height of a tower crane is 265 feet; the maximum reach of the jib is 230 feet, and the maximum lifting strength is 19.8 tons.   

Before it is ready for use, a tower crane is stabilized at the jobsite by constructing a concrete pad that is embedded with large anchor bolts used to secure the base of the crane.  When the crane reaches its maximum height, it is tied to the side of the skyscraper with steel collars so it can move upward as needed. 

The gears and motor of the crane are contained in the slewing unit, which is attached to the mast and allows the crane to rotate.   Set on top of that is a long jib used to lift the heavy materials and a counter-jib that is used as a counter-weight to keep the crane balanced.  A crane operator controls the unit from the ground or in a cab located on the top of the tower.

The mast of the crane is comprised of a series of vertebras generally 10 square feet in size.  Once the crane is fastened to the exterior of a building, or in some cases to the interior, a process is started to build the crane taller by adding new vertebra pieces.  The climbing frame, which sits just below the slewing unit and on top of the tower, temporarily supports that section of the mast as the jib moves a new segment into place.  After the new piece is bolted down, the climbing frame moves up higher along the mast to get ready to repeat the process. 

Conco’s mission is to be the best supplier of concrete services in the Western United States and to bring expertise, experience and quality to each project.  We continue to upgrade and expand facilities to better serve the growing market for public works projects, commercial, parking structures, educational, and other construction development. We serve California, Washington State, Oregon, Colorado and Nevada.

Source: en.wikipedia.org/wiki/Crane_(machine)#Tower_crane  

Many of Conco’s Projects have LEED Certification

Many of the projects that The Conco Companies are involved with incorporate energy efficient and “green” sustainable features to not only construct better buildings but also to achieve LEED certification.  So what is LEED and why would the construction industry try to achieve a higher LEED rating?  To start with, LEED (Leadership in Energy and Environmental Design) is the most widely recognized green building rating system in the world. 

The U.S. Green Building Council (USGBC) started LEED in 1998 with the intent to provide third-party guidelines for the building industry to design, construct, and operate buildings that provide the most optimal environment as possible.  The standards used by LEED are reviewed and publically updated periodically by the USGBC that has almost 20,000 members.  LEED is important as it promotes and rewards energy efficiency along with the protection of renewable resources. 

USGBC explains that for new construction, achieving a higher LEED certification can improve the market demand for the building over non-LEED certified buildings.  Furthermore, the occupants of a LEED rated building benefit by being in a healthier environment.

The LEED system uses certifications based on the organization’s guidelines to recognize buildings that achieve these goals.  Certifications include Silver, Gold, and Platinum (the highest achievement).  At each level, the following five categories determine how points are awarded:  Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, and Indoor Environmental Quality. 

Certification levels are improved by such things as installing heating and cooling systems as well as energy-efficient appliances.  Ratings are also improved with the use of recycled materials.  Additional recognition may be achieved in other categories such as Innovation in Design or Regional Priorities.  Points in Regional Priorities are earned when a builder is recognized for going to great lengths to lessen or eliminate the harmful impact on an area’s sensitive environment.  LEED endorsements are used for commercial and industrial buildings, residential homes and whole neighborhood projects.  

 

The Conco Companies is one of the leading concrete contractors in the Western U.S. and offer a wide range of quality services and products.  While we tackle projects both big and small, our experience includes providing the complete concrete package for the Levi’s Stadium along with other notable projects.  We serve California, Washington State, Oregon, Colorado and Nevada.

Two Innovation Schwing S 36 X Boom Pumps Join Our Fleet

The Conco Companies have owned and operated one of the largest concrete pumping companies in the United States for more than 40 years.  Our extensive experience has made us leading experts in delivering cost-effective, quality solutions for even the most challenging projects. One of the reasons why we can accomplish this is that we own one of area’s largest fleet of concrete boom pumps and ancillary equipment.  The newest addition to our fleet includes two powerful and reliable Schwing S 36 X concrete boom pumps.

Conco was the first company to purchase the Schwing S 36 Xs with a new tremie option that allows users to safely support up to 1,100-pounds from the boom. Schwing America states that the “new tip section can be used to support a tremie pipe up to 45-feet long providing the wall thickness is not more than .125-inches. This new option eliminates the need for a crane to support the tremie pipe.”   

At Conco we have always believed that a large part of getting the job done right is having the proper equipment.  Our purchase of the two S 36 Xs will allow us to more cost-effectively serve project specific challenges of our drilling customers.  One of the primary reasons that the Roll and Fold boom design is the most effective for tremie applications is that the full 180 degrees articulation at the 2/3 knuckle is on the working side of the boom.  

Our new boom pump also features the VECTOR control system that offers two-way communication between the concrete pump and operator from the radio remote box.  The VECTOR system also includes a record keeping system used for managing maintenance.  See our website to learn more about our newest additions as well as all of our other concrete pumps. 

Conco’s mission is to be the best supplier of concrete services in the Western United States and to bring expertise, experience and quality to each project.  We continue to upgrade and expand facilities to better serve the growing market for public works projects, commercial, parking structures, educational, and other construction development. We serve California, Washington State, Oregon, Colorado and Nevada.

Putzmeister TB 105

Our latest addition to The Conco Companies’ extensive fleet includes the Putzmeister Telebelt® TB 105 Telescopic Belt Conveyor.  The new Telebelt will be put to good use and allow us to quickly convey a wide variety of materials ranging anywhere from sand to 4-inch rock.

Our new Putzmeister TB 105 has the operating capacity of up to 360 cubic yards per hour and provides a cost-effective alternative to transporting materials by using a crane and skid-steer.  By offering the advantage of requiring less manpower and smaller handling machinery, our crews will be able to place material at a high volume. 

The TB 105’s broad range of hopper options brings to our projects the benefit of its adaptiveness to a variety of job specifications.  In addition to its easy set-up, it offers the ability to operate on a jobsite with a low clearance (under 16 feet).  Furthermore, the TB 105 can handle concrete from 0” to 12” slumps. Other highlights of the new Putzmeister Telebelt® are the 105 feet horizontal reach and a large 18” wide conveyor belt.  

A few of our new Putzmeister’s options include a conveyor horizontal reach of a maximum at 0° and 105’ (32.00m).  It has a feed conveyor length of 40 feet long and a 15 foot trunk/end hose length.  The discharge height has a maximum of 30° 58’ 8”.  

Owning such an impressive fleet of concrete boom pumps, Telebelts and ancillary equipment has contributed to Conco being one of the largest concrete pumping and belting companies in the U.S.  It gives us the capability and resources to handle even the most difficult project requirements.  We only buy top quality equipment such as from Putzmeister America, a global leader in manufacturing concrete and material placing equipment that is proudly made in America.  Please visit our website for more specifications on the new pump along with information on the rest of our fleet of concrete pumps and Telebelts. 

The Conco Companies are one of the foremost suppliers of concrete services for the Western U.S. We got our start in 1959 in the Bay Area by offering clients the best value on a broad range of concrete services and products.  Since that time, we have taken a leading role as top concrete contractors in the region. We have four regional offices serving California, Oregon, Nevada, Colorado and Washington.

Five Distinct Classes of Chemical Admixtures

The purpose of chemical admixtures is to give concrete additional properties in order to better handle a range of variables such as pumping requirements or placing concrete in extreme weather conditions.  According to the National Ready Mix Concrete Association (NRMCA), admixtures are added to concrete to increase “durability workability or strength characteristics of a given concrete mixture.”  

 

The Portland Cement Association further adds that, “Admixtures are classed according to function. There are five distinct classes of chemical admixtures: air-entraining, water-reducing, retarding, accelerating, and plasticizers (superplasticizers).” 

 

Air-entraining is the process of intentionally inserting microscopic air bubbles into the concrete.  It is done to improve the concrete’s workability as well as to increase its durability in extreme freezing and thawing temperature cycles.  The only downside to air-entraining is that the concrete experiences a 5% reduction in strength for each 1% of air added; however, the segregation and bleeding is diminished or completely eliminated. 

 

Accelerators are another type of chemical admixtures and are used to increase the early strength of concrete by causing it to harden faster.  They are also used to protect concrete from extremely cold weather or if a project has a tight deadline.  Chemical accelerators can be either chloride based or non-chloride based and one common inexpensive example is calcium chloride. 

 

For situations where you need to slow down or delay the hardening process such as requiring a slower pour due to the scope of the project or in very hot temperatures, a retardant may be used.  This gives crews more time to effectively place and finish the concrete.   Sugars, lignin, and citric and tartaric acids are all common retardants. 

 

Chemical admixtures can be in a liquid or powder form and are added to the concrete mix along with portland cement, aggregate and water and typically make up less than 5% of the total concrete mix.  Regardless of whether chemical admixtures are derived from natural or manufactured chemicals, they are added to the concrete either immediately before or during the mixing process.

 

At The Conco Companies, our mission is to be the best supplier of concrete services in the Western United States and to bring our expertise, experience and quality to each project.  We continue to upgrade and expand facilities to better serve the growing market for public works projects, commercial, parking structures, educational, and other construction development. We have offices in California, Washington State, Oregon, Colorado and Nevada.

Sources:cement.org/cement-concrete-basics/concrete-materials/admixtures, nrmca.org/aboutconcrete/cips/15p.pdf

Properly Cured Concrete Offers an Optimal Outcome

Curing concrete is the process that controls the rate and amount of moisture concrete loses during cement hydration.  When concrete is properly cured, it can attain its optimal strength and durability.  Curing can be done at the jobsite once the concrete is placed and finished or during the manufacturing of concrete products.   

 

There are several different methods for curing concrete that are determined by factors such as the type of construction, the concrete mix, and outside temperature and humidity.  Regardless of the technique used, they all strive to keep concrete moist and to prevent the loss of moisture.  Other considerations taken into account are project specifications and/or parameters of the jobsite.  The Portland Cement Association explains that the purpose of curing is to provide the “adequate amount of moisture for continued hydration and development of strength, volume stability, resistance to freezing and thawing, and abrasion and scaling resistance.”

 

Concrete attains its full strength and durability after curing for a number of days, or in some cases, weeks.  Concrete contractors prevent the loss of moisture during curing by leaving the formwork in place and/or to cover the concrete with an impervious paper, plastic sheeting or membrane-forming compounds.  In addition methods such as spraying (or fogging), ponding or wet coverings that cool the concrete as the water evaporates are used.

 

When temperatures are 40ºF and above, the American Concrete Institute (ACI) recommends a curing period of a minimum of 7 days, or until 70% of the specified compressive strength is achieved for most concrete structures.  In temperatures above 50ºF, an accelerant can be used to speed up the hardening process and reduce the curing period to only 3 days.  Additional variables are determined by the weather conditions the concrete will be exposed to during its life-cycle as well as the size, shape and strength requirements.   

 

The Conco Companies are a leading supplier of concrete services for the Western U.S. and 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 taken a leading role as one of the top concrete contractors in the region. Our offices serve California, Colorado, Oregon, Washington and Nevada.

Sources:cement.org/for-concrete-books-learning/concrete-technology/concrete-construction/curing-in-construction, concrete.org/TopicsinConcrete/TopicDetail.aspx?id=25&Search=Curing