Production Control in Earthworks: Concepts and Metrics

The lean construction theoretical lens afforded by the Transformation-Flow-Value (TFV) theory has led to changes in the way production is understood in building construction projects. However, this new perception of production has not taken root in the earthworks and infrastructure sectors, primarily because of the difficulty in discerning what the products are and how they flow. This research addresses the fundamental question of production flow in the specific context of earthworks. It proposes a novel lean view of production flow in earthworks, and it validates the proposed model by developing and testing assessment procedures for evaluation of the quality of production flow. Its metrics apply measurements of throughput, cycle time, work in progress, and waste to enable improved situational awareness for effective decision making in managing execution of earthworks onsite. The measurements use monitoring data acquired from machine control technologies, linked to a specialized information schema developed to represent continuous elements (e.g., road courses or landfills) using discrete elements. The procedures are demonstrated on a reservoir embankment construction project. Three different theoretical production scenarios are presented to illustrate the applicability of production theory and of the metrics and procedures to the context of earthworks

A specialized information schema for production planning and control of road construction

Building Information Modelling (BIM) and the IFC information schema are well developed to suit building construction projects. Not only do they represent the building as a designed product, they can also be used to support Lean production planning and control. Road construction, a sub-type of civil infrastructure construction, is fundamentally different to building construction, in terms of its products, the types of work and operations, and the resources used. One of the key differences from the point of view of production flow, is that roads are composed of geometrically continuous courses rather than discrete ‘products’, making work packaging difficult. We propose a product schema which models road sections with distinct road course segments that are dynamically defined aggregations of roadels (fine-grained vertical triangular prism objects). The schema represents the continuous nature of road construction. Its discrete entities also enable computations of as-made work using the raw data obtained from sensors and surveys, thus enabling systematic analysis not only of machine productivity and utilization rates, but also of Lean production flow metrics. Finally, we demonstrate how the proposed schema can be implemented with existing IFC entities, but conclude that extending the schema with new entities is preferable for both semantic and practical reasons

Production process evaluation for earthworks

Production in earthworks projects is a continuous process of strictly sequenced operations performed by heavy machinery on site. The Production Process Evaluation (PPE) index was developed to evaluate these types of processes by quantifying waste in the bottleneck operation. The PPE index is the ratio of the actual production volume to the theoretical maximum production volume, and it is calculated by assessing value adding and non-value adding times, actual and theoretical throughput, and shift durations. These are computed using data obtained from machine control systems linked to the roadel information schema, which represents continuous products and processes. The PPE index was implemented on a case study of a water reservoir construction project. The spreading operation was identified as the bottleneck in the process, based on the high levels of inventory waiting for the operation, the high capacity utilization in the operation and the low capacity utilization of the predecessor and successor operations. The PPE index ranged from 45% to 54% during the three weeks of the case study and indicated high levels of waste in the bottleneck and a lack of production management

Roadels: Discrete information objects for production planning and control of road construction

Road construction is fundamentally different to building construction, in terms of its products, the types of work and operations, and the resources used. One of the key differences from the point of view of planning and control of production flow is that roads are composed of geometrically continuous courses rather than discrete 'products', making work packaging difficult. Clearly defined work packages that comprise work performed on distinct products are central to lean construction methods of planning and control, such as the Last Planner System. We therefore propose a product schema which models road sections with distinct road course segments that are dynamically defined aggregations of 'roadels'. A roadel is a fine-grained vertical triangular prism object that can be dynamically aggregated with other roadels to represent a road course segment associated with a work package, a planned task, or an as-built section. The schema represents the continuous nature of road construction, and its discrete entities enable representation and computations of as-made work using the raw data obtained from machine-mounted sensors and land surveys. We describe the information schema and illustrate its use for computation and analysis of lean production flow metrics. The schema has been tested using case study data from a 25,000 m2 parking lot project, which was modeled with more than 560,000 roadels with as-made status data collected from 33 working days over a period of two months

Overcoming "but we're different": An ipd implementation in the middle east

What are the key success factors and barriers that can be expected when implementing Integrated Project Delivery (IPD) for the first time in a traditional construction culture? We present an in-depth case study of the "Saxum" project under construction in Abu Ghosh, Israel, the first implementation of IPD in this traditional construction culture. The goal is to glean insight into the dynamics that support and/or subvert the required paradigm shift. The researchers interviewed the key participants, visited the site and reviewed source material from this and other IPD projects. Despite cultural and historical factors that were expected to prevent or weaken implementation of a collaborative approach like IPD, the key participants built the project according to the IPD framework. The insistence of the overseas project owner's representative that IPD be employed, coupled with the openness of the local partners to work differently, were found to be critical success factors. The participants' mindset and their behavior changed fundamentally with respect to their traditional roles, as did the character of the project (which was measured on a multi-factor sliding scale from "traditional" to "pure IPD"). Prior to this successful implementation, the opinion of local practitioners on IPD could be summed up as: "Nice in theory, but not applicable in our adversarial construction business culture." Yet this project has shown that given the right combination of agents, it is not only feasible but also rewarding to adopt. While there are multiple accounts of IPD implementations, we focus here on viewing the case study through the lens of change management with an analysis of the local cultural barriers that were overcome

Bone fractures from generalized convulsive seizures and status epilepticus-A systematic review

We present a systematic review of the literature regarding types and anatomic distribution of fractures in association with generalized convulsive status epilepticus (GCSE) and convulsive seizures in adult patients accompanied by an illustrative case of a patient with GCSE and diffuse postictal pain from underlying bone fractures.; The library search engines PubMed and EMBASE were screened systematically using predefined search terms. All identified articles written in English were screened for eligibility by two reviewers. The preferred reporting items for systematic reviews and meta-analyses guidelines were followed.; The screening of 3145 articles revealed 39 articles meeting the inclusion criteria. Among all fractures, bilateral posterior fracture-dislocations of the shoulders were reported most frequently (33%), followed by thoracic and lumbar vertebral compression fractures (29%), skull and jaw fractures (8%), and bilateral femoral neck fractures (6%). Risk factors for seizure-related fractures are seizure severity, duration of epilepsy, the use of antiseizure drugs known to decrease bone density, and a family history of fractures. Based on these findings, a three-step screening procedure is proposed to uncover fractures in the postictal state. All studies were retrospective without standardized screening methods for seizure-associated fractures resulting in a very low level of evidence and a high risk of bias.; Posterior fracture-dislocations of the shoulders, thoracic and lumbar vertebral compression, fractures of the skull and jaw, and bilateral femoral neck fractures are most frequently reported. Preventive measures including bone densitometry, calcium/vitamin D supplementation, and bisphosphonate therapy should be reinforced in epilepsy patients at risk of osteoporosis. As long as the effect of standardized screening of fractures is not investigated, it is too early to integrate such a screening into treatment guidelines. In the meantime, clinicians are urged to heighten awareness regarding seizure-associated fractures, especially in patients with postictal pain, as symptoms can be unspecific and misinterpretation may impede rehabilitation