Incorporating Constructability in the Design of Masonry Structures

The International Building Code (IBC) has now been adopted as the model design code for most states and territories of the United States of America. For Masonry design, the IBC references the Building Code Requirements and Specification for Masonry Structures (MSJC) for material properties, design procedures, specifications and quality control. Individual state codes then amend the two documents (IBC and MSJC) appropriately. In high seismic regions of the United States, hollow block of concrete masonry units (CMU) are the material of choice in masonry construction. The CMU’s are built using sand, pea gravel, cement and water. CMU is typically delivered to the job site as a individual units usually sixteen inches long, eight inches high and of thickness varying between six inches to twelve inches nominal dimensions as required. Building of a masonry system requires the use of mortar applied at the bed and head of the CMU blocks and grout to fill in the hollow voids in the CMU where steel reinforcement is used. The mortar and the grout are made by proportioning amounts of cement, sand, pea gravel and water as specified by design codes. This paper presents teaching methods used to teach undergraduate architectural (with emphasis in structural) engineering masonry design courses. The format used exposes the students to instructors that are current consulting engineers and with vast practical knowledge with masonry. The design using masonry at element level is taught in a lecture format. In this format, factors influencing design of the built masonry unit are investigated by building wall units. This hands on “learn by doing” exposes the students to constructability and quality control requirements. Prism tests are also conducted to familiarize the students to the possibility of debonding of the masonry from the mortar. Design using the materials at a system (building) level is then taught in a laboratory format. In this later format, the students prepare complete construction documents (structural calculations, structural plans and structural specifications) for real masonry structures using architectural plans. Understanding of the construction process of masonry structures is highly emphasized in the process of preparing the construction documents. As a result of this two tier coverage of design of masonry structures, graduates from this program have earned a reputation in California of “being ready on day one” after graduation on designing these types of projects

International sustainability through knowledge transfer considering culture and resources – Sledgehammer attacks on adobe masonry walls

In terms of knowledge and technology innovation, sustainability is defined as the ability for a society or culture to develop, incorporate and maintain knowledge and technology in a long term manner without continued outside input. In rural East Africa, the prevalence of low-cost building materials and unskilled labor produce buildings that provide poor security for charitable groups working to improve the quality of life for communities and individuals there. Medicine and other medical supplies are targeted by thieves for their high value. Buildings constructed of the most common building material in the region, adobe masonry, are easily broken into by using sledgehammers to destroy a portion of a wall, circumventing many security measures. The people associated with Nyumbani Village (a project located in a rural area of Kenya) asked for help in mitigating this problem. The question was asked if local resources (low cost and high availability) could be used in a manner that could be easily and affordably reproduced. This paper will present, in a qualitative manner, how a sustainable solution was found for sledgehammer attacks on adobe masonry walls

Holistic Interdisciplinary Design - Everyone Does Everything (Engineering Students as Sculptors)

The ability to offer students an interdisciplinary experience under a team work setting is invaluable in preparation for a career in the built environment. A hands-on approach coupled with a real project presents unique opportunities in student learning. Learning in regards to the dynamics of team personalities, deadlines, approval procedures, and deliverables. One such hands-on based real project was to design, build, and install an 800 lb., 20 ft. long, and 10 ft. tall sculpture. The sculpture was to be built of recycled steel of a mustang in 10 weeks for the University’s library Spring 2016 exhibit. The project gave the students direct exposure to the phases required to take a highly constrained construction project from conception to completion (Impacted Project Delivery). Under the constraints of limited time, limited budget, unique materials, university regulatory requirements, and confined site location (second floor of library), the students learned how impacted constraints affect the design, engineering, and construction process. This paper outlines the methods used by the faculty adviser to facilitate student success

Using K’nex to Teach Large Scale Structures to Architects and ConstructionStudents

The College of Architecture and Environmental Design at California Polytechnic State University in San Luis Obispo (Cal Poly SLO) is the only college in the nation that includes architecture (ARCH), architectural engineering (ARCE) and construction management (CM) programs in the same college. Given the unique mix of disciplines and the emphasis on interdisciplinary collaboration, the ARCH and CM students take a five-course structural engineering sequence from the ARCE department. A challenge of these courses is to maintain some degree of computational rigor while offering a broader perspective that will benefit the ARCH and CM students. This paper reports on one means of accomplishing this using K’nex toys to illustrate the entire design -construction sequence and relate how structure fits into this process during the sequence’s culminating course

Preparing Students for the Environment of the Practice of Consulting Engineer

In the United States of America, the body of knowledge required for an individual to be allowed to take the engineering licensing examination, which on passing allows the individual to be in responsible charge of engineering projects, is usually defined by laws and regulations of each state. In California, the shortest path taken by most individuals is one where the individual graduates from an ABET accredited undergraduate program; passes the Engineer in Training (EIT) examination and works under the supervision of a licensed engineer for two years (one year if the individual has a Masters degree in relevant field). In order to better prepare the student to enter the practice of engineering, and thus give the student an immediate level of comfort with the real world environment, practical design needs to be directly incorporated into the teaching of design. This paper presents teaching methods used to teach undergraduate architectural engineering design courses, where the discipline of concentration is structural engineering. The format used exposes the students to instructors that are current consulting engineers and to courses that are modeled in line with the structural engineering profession. The theory, of construction materials (concrete, steel, masonry and timber) is covered for each material at element level in a lecture format. Design using the materials at a system level (building) is then taught in a laboratory format. In this later format, the students prepare complete construction documents (structural calculations, structural plans and structural specifications) for real projects using architectural plans. This “learn by doing” format has proven-over time-to prepare the students to the same environment that the students face after graduation. It is generally an accepted fact in the structural profession in California that, graduates from Architectural Engineering program (ARCE) at California Polytechnic State University (CAL POLY) “hit the ground running from day one”. This is attributed to the familiarity, of the design office environment, obtained during their undergraduate education. The familiarity is acquired through the design laboratories taught by design professionals

No Admixture, Sustainable, Self-Consolidating Grout

The consolidation of grout in concrete masonry unit (CMU) walls is labor-intensive. Also, the grout’s Portland cement content has a high embodied energy demand – a non-sustainable characteristic. For the labor-intensive issue, chemical admixture self-consolidating grouts have been used in walls 12.67 ft. (3.86 m) tall, however the chemical additive can impose new limitations on the grout (non-robust characteristics). No admixture self-consolidating grout with high percentage Portland cement replacement have potential for robust and sustainable application. This paper reports on the consolidation of no admixture self-consolidating grout made by substituting high percentages of Portland cement with Type-F fly ash and/or GGBFS. The percent replacement ranged from 50% to 80% by volume. Single lift test CMU walls were 12.67 ft. (3.86 m) tall. The relative reinforcement consolidation was assessed by comparison to traditional mechanically consolidated grout and also compared to criteria of ACI technical notes for shotcrete. Cure time was 125 days

Performance of no vibration / no admixture masonry grout containing high replacement of Portland cement with fly ash and ground granulated blast furnace slag

When hollow concrete masonry is used for construction in high seismic regions, structural designs typically require fully grouted walls. For a fully grouted 203x203x406 mm (8x8x16) concrete masonry unit (CMU), 52 percent of total volume is grout. Grouting process is labor-intensive, time consuming and has a high energy demand due to requirements of consolidation in each and subsequent grout lifts. Self-consolidating grout with admixtures has been successfully used without segregation in walls of up to 3.86 m (12.67 ft.) in height. Investigation of self-consolidating grout mixes without admixtures has potential for sustainability improvement. This paper reports on the compression strength and consolidation observations of self-consolidating characteristics of no vibration/no admixture grout made by substituting various proportions of Portland cement with Type F fly ash and/or ground granulated blast furnace slag (GGBFS). The percentages of Portland cement replacement were 0%, 50%, 60%, and 70% for Type F fly ash replacement. The percentages of Portland cement replacement were 0%, 60%, 70% and 80% for Type F fly ash and GGBFS. Compression test specimens were made from individual 203x203x406 mm (8x8x16) concrete masonry hollow core units, where the cells were filled with no vibration/ no admixture grout. The specimens were dry cured and compression testing performed at 7, 14, 28, 42, 56, and 130 days. Consolidation testing specimen walls were 3.86 m (12.67 ft.) tall by 1.22 m (4.0 ft.) long with 203x203x406 mm (8x8x16) CMU. The relative performance assessed by comparing to traditional grouted masonry and evaluating consolidation characteristics around mortar fins and reinforcement at 130 days as well as compressive strength of the grout at various wall heights

Intrapartum Antibiotic Chemoprophylaxis Policies for the Prevention of Group B Streptococcal Disease Worldwide: Systematic Review.

Background: Intrapartum antibiotic chemoprophylaxis (IAP) prevents most early-onset group B streptococcal (GBS) disease. However, there is no description of how IAP is used around the world. This article is the sixth in a series estimating the burden of GBS disease. Here we aimed to review GBS screening policies and IAP implementation worldwide. Methods: We identified data through (1) systematic literature reviews (PubMed/Medline, Embase, Literature in the Health Sciences in Latin America and the Caribbean [LILACS], World Health Organization library database [WHOLIS], and Scopus) and unpublished data from professional societies and (2) an online survey and searches of policies from medical societies and professionals. We included data on whether an IAP policy was in use, and if so whether it was based on microbiological or clinical risk factors and how these were applied, as well as the estimated coverage (percentage of women receiving IAP where indicated). Results: We received policy information from 95 of 195 (49%) countries. Of these, 60 of 95 (63%) had an IAP policy; 35 of 60 (58%) used microbiological screening, 25 of 60 (42%) used clinical risk factors. Two of 15 (13%) low-income, 4 of 16 (25%) lower-middle-income, 14 of 20 (70%) upper-middle-income, and 40 of 44 (91%) high-income countries had any IAP policy. The remaining 35 of 95 (37%) had no national policy (25/33 from low-income and lower-middle-income countries). Coverage varied considerably; for microbiological screening, median coverage was 80% (range, 20%-95%); for clinical risk factor-based screening, coverage was 29% (range, 10%-50%). Although there were differences in the microbiological screening methods employed, the individual clinical risk factors used were similar. Conclusions: There is considerable heterogeneity in IAP screening policies and coverage worldwide. Alternative global strategies, such as maternal vaccination, are needed to enhance the scope of global prevention of GBS disease