Construction Engineering Commons^™

No Admixture, Sustainable, Self-Consolidating Grout, Craig V. Baltimore Dr

Craig V. Baltimore

ABSTRACT: 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 …

Decorative Ferrocement Elements, Letitia Nadasan, Traian Onet, Ana Ioana Petean, Marian Sabau

Marian Sabau

Ferrocement has the versatility that can be 'sculptured' or shaped into numerous fascinating structures and objects for very wide applications. The exposure of this technology to engineers in general is rather minimal in Romania and many are skeptical about it. The potential is not exploited for it being unconventional in nature. Its ability to compete or use as a cheaper alternative and yet a promising technology in ensuring improved living standard and environmental quality must not be neglected. The paper discusses about the applicability of ferrocement in the Romanian scene with respect to recreation and home use. The ferrocement elements …

Experimental Determination On Bond Strength Of Rebar In Self-Compacting Concrete, Marian Sabau, Traian Onet, Ana Ioana Petean

Marian Sabau

Experimental results of the local bond stress-slip relationship of deformed reinforcing bars embedded in confined self-compacting concrete are presented. A total of 58 pull-out specimens were tested. Each one of these specimens simulated the confined region of a beam-column joint. The main analyzed parameters were the concrete type, the confining reinforcement, the reinforcement bar diameter, the embedded length of bars. The results showed that in order to ensure that the bond failure is caused by pull-out, a restraining reinforcement must be provided. The paper also presents a comparison between self-compacting concrete (SCC) and normally vibrated concrete (NVC).

Economia De Energie Realizată Prin Folosirea Betonului Autocompactant, Marian Sabau, Traian Onet, Ana Ioana Petean, Letitia Nadasan

Marian Sabau

Betonul autocompactant (BAC) este un beton inovativ care nu necesită vibrare în momentul punerii în operă, acesta fiind capabil să curgă sub propia greutate, poate să umple complet cofrajele şi să ajungă la o compactare corespunzătoare fără a fi nevoie de o compactare mecanică. Această lucrare prezintă avantajele acestui nou tip de beton, materialele constituente, metodele de testare, precum şi dezavantajele care le aduce compactarea prin vibrare asupra betonului obişnuit. Eliminarea vibrării are de asemenea efecte benefice asupra condițiilor de muncă în procesul de producere al betonului.

Effect Of Confinement On Bond Strength Between Self-Compacting Concrete And Reinforcement, Marian Sabau, Traian Onet, Ana Ioana Petean

Marian Sabau

Slippage of the beam reinforcement at beam–column connections is an important cause of damage of reinforced frames under static and dynamic loads. This paper presents the effects of confinement in self-compacting concrete (SCC), on the local bond stress vs. slip characteristics of deformed bars in reinforced concrete joints. Prismatic specimens with deformed steel bars embedded for a fixed length equal to three and five equivalent diameters were tested under monotonic loading. The specimens represented the confined region of a beam–column connection. The obtained results indicated that as far as the bond splitting cracks are restrained by reinforcing bars crossing these …

Bond Between Self-Compacting Concrete And Reinforcement, Marian Sabau, Traian Onet, Ioan Pop

Marian Sabau

This paper study the bond behaviour of self-compacting concrete (SCC) in comparison to normal vibrated concrete (NVC). In this paper are presented the following parameters: the influence of bar diameter, the influence of concrete quality, the top-bar effect, the influence of active and passive confinement. In literature, different test results are found for the bond strength in SCC, which deliver contradictory results, but internationally it seems to be agreed that bond strength in SCC is slightly higher than NVC.

Hardened Properties Of Self-Compacting Concrete, Marian Sabau, Traian Onet, Ana Ioana Petean

Marian Sabau

This paper presents the properties of hardened self-compacting concrete (SCC) and compare them to those reported for normally vibrated concrete (NVC). The mechanical properties evaluated are: compressive strength, modulus of elasticity, tensile strength, creep, shrinkage and bond with reinforcement. The very wide range of materials and mixes already used for SCC produced a significant scatter of data, but clear conclusions have been obtained. The compressive strength of SCC was likely to be the same or greater than that of NVC by using the same content of cement and water. Modulus of elasticity of SCC was lower than that of NVC …

Historic Building Information Modelling Phd, Maurice Murphy

Maurice Murphy

Historic Building Information Modelling (HBIM) is a novel prototype library of parametric objects, based on historic architectural data, in addition to a mapping system for plotting the library objects onto laser scan survey data. The HBIM process begins with remote collection of survey data using a terrestrial laser scanner. This is then followed by the processing of the laser scan survey data to generate ortho-image and segmented point cloud data for mapping of library objects. The next stage involves the design of new shape and parametric rules for the construction of a library of objects that are based on 18th …

An Overview Of Component Unit Pricing Theory, David Cattell

David Cattell

Component unit pricing (CUP) theory presents a fresh approach to item pricing, described as the process of distributing the overall price among its constituent component items. This theory provides explanation and proof that different distributions of mark-up among the items of a project produce different levels of reward for contractors, while exposing them to different degrees of risk. The theory describes the three identified sources of these rewards, namely those of improved cash flow, escalation in compensation and valuations of likely variations. In addition, it also provides the first explanation of the three risks involved, namely the risk of ‘rejection’, …

The Bonds That Tie: Will A Performance Bond Require That A Surety Deliver A Certified Green Building?, Darren Prum, Lorilee Medders

Darren A. Prum

In 2006, the city of Washington, D. C. passed landmark legislation that introduced green building requirements for various types of structures into the jurisdiction over a five-year period. A noteworthy aspect of the legislation directed construction projects within the district to purchase green performance bonds up to $3 million to guard against a privately owned project’s failure to meet its green building aspirations. In essence, this law placed the burden of guaranteeing compliance with the government’s policy upon the contractors and sureties of a green building project.

Following the passage of this act, confusion amongst the construction industry and sureties …

Nonlinear Concrete Behaviour, Marian Sabau, Traian Onet

Marian Sabau

This paper presents an overview of nonlinear behaviour in reinforced concrete structures. Structural concrete is a nonlinear material both at strength limit states and service loads. Are presented terms of effects that are primarily observed in concrete, steel or a combination of the two. When considering nonlinear behaviour, an important aspect is whether or not strain localization will occur as size effects. The model must first be validated by experiments and benchmark tests to ensure the safety and reliability criteria. In nonlinear finite element procedures, engineers must check their finite element discretization and modelling assumptions used in their analyses. Advanced …

A Simplified Unbalanced Bidding Model, David William Cattell, Paul Anthony Bowen, Ammar P. Kaka

David Cattell

Much research effort to date has focused on the development and use of bidding models in optimizing contractors' bid prices in competitive tendering environments. Unbalanced bidding models, in particular, have the objective of maximizing a project's prospective profits by using techniques of applying differentiated mark-ups to all of a project's items of work. It is shown here that these unbalanced bidding models have been unnecessarily complicated by incorporating consideration of a project's item costs. Bidding models can be significantly simplified by having the objective of maximizing a project's top-line revenue rather than maximizing bottom-line profit. A new model, incorporating all …

Review Of Unbalanced Bidding Models In Construction, David W. Cattell, Paul A. Bowen, Ammar P. Kaka

David Cattell

Unbalanced bidding describes an activity otherwise known as item price loading. It is a practice used to some extent by building contractors to determine the prices that they will allocate to the individual component items within a project. This practice takes advantage of the contractor’s opportunity to manipulate these prices without this affecting their overall bid price for a project. Three types of loading are described, namely those of “front-end loading”, “back-end loading”, and “quantity error exploitation” (otherwise known as “individual rate loading”). Several scientists have expressed an interest in this field, starting with Marvin Gates in 1959. All of …

A Model To Distribute Mark-Up Amongst Quotation Component Items: An Outline, David Cattell, Paul A. Bowen, Ammar P. Kaka

David Cattell

The outline of a proposed new unbalanced bidding model is discussed. Background is provided as regards the role of item price loading, otherwise known as unbalanced bidding. Three types of loading are described, namely those of ‘front-end loading’, ‘back-end loading’ and ‘quantity error exploitation’ (otherwise known as ‘individual rate loading’). It is proposed that one single mathematical model could embrace all three of the above types and that the aspect of risk may be addressed partially by means of using the quadratic programming techniques employed within the field of Modern Portfolio Theory. MPT is a field pioneered by Markowitz in …

Ecocomposite Materials, David A. Bainbridge

David A Bainbridge

If we are wise we can make a transition to the Age of Ecocomposites with virtually no pollution. Ecocomposite materials are those made with natural fibers and resins and can be produced in sustainable agro-industrial ecosystems. These materials can reused, recycled or returned to nature by grinding, composting, biological breakdown, or benign solvents. Historical use and recent rediscovery of these materials has suggested the many advantages (and challenges) using these materials offer to designers and engineers.