The cone loading test to estimate deformability moduli of a tropical soil

The Cone Loading Test (CLT) consists of the execution of a load test on the piezocone probe in conjunction with the CPT test. The CLT yields the modulus ECLT, a parameter that can be used in the estimative of foundation settlement. It is also presented here the interpretation and the process to determine ECLT values from the stress-displacement curves obtained from cone loading tests. Several CLT tests were conducted at the experimental research site of São Paulo State University, Bauru-SP-Brazil. The geotechnical profile at the studied site is a brown to bright red slightly clayey fine sand, a tropical soil common to this region which is lateritic, unsaturated and collapsible. The results of CLT tests satisfactorily represent the behavior of the investigated soil. The penetrometric modulus ECLT for each depth was calculated considering the elastic behavior in the initial linear segment of the soil stress-strain curve. The ECLT moduli obtained for the various tests were compared to moduli obtained from PMT and DMT test results performed at same studied site. The shear modulus degradation curves obtained from the CLT tests are also presented. The comparison to PMT and DMT results indicates the CLT test is a viable complementary test to the CPT in the quest for better understanding stress-strain behavior of soils. Further, the CLT test provides a graphic visualization of the degradation of the shear modulus with increasing levels of strain. As a hybrid geotechnical test, CPT+CLT can be valuable in the investigation of non-conventional collapsible soils, whose literature lack reference parameters for the prediction of settlement in the design of foundations.

Discriminative ability of functional loading tests for adolescent jumper's knee

Objective. To investigate the reliability and validity of five squat-based loading tests that are clinically appropriate for jumper's knee. The loading tests were step up, double leg squat, double leg squat on a 25-degree decline (decline squat), single leg decline squat, and decline hop. Design. Cross-sectional controlled cohort. Subjects without knee pain comprised controls, those with extensor tendon pain comprised the jumper's knee group. Setting. Institutional athlete study group in Australia Participants. Fifty-six elite adolescent basketball players participated in this study, thirteen comprised the jumper's knee group, fifteen athletes formed a control group. Intervention. Each subject performed each loading test for baseline and reliability data on the first testing day. Subjects then performed three days of intensive (6 h daily) basketball training, after which each loading test was reexamined. Main outcome measures. Eleven point interval scale for pain. Results. The tests that best detected a change in pain due to intensive workload were the single leg decline squat and single leg decline hop. This study found that decline tests have better discriminative ability than the standard squat to detect change in jumper's knee pain due to intensive training. The typical error for these tests ranged from 0.3 to 0.5, however, caution should be exercised in the interpretation of these reliability figures due to relatively low scores. Conclusions. The single leg decline squat is recommended in the physical assessment of adolescent jumper's knee. The decline squat was selected as the best clinical test over the decline hop because it was easier to standardise performance.

Electromyographic fatigue threshold of erector spinae muscle induced by a muscular endurance test in health men

Purpose: To identify the electromyographic fatigue threshold in the erector spinae muscle. Methods: Eight 19 to 24-year-old male volunteers participated in this study, in which surface electrodes were used, as well as a biological signals acquisition module (Lynx) with a sampling frequency of 1000Hz, a 1000 times gain, a 20Hz high pass filter and a 500Hz low pass filter. The test consisted of repeated isometric contractions of the erector spinae muscle in a 45° hip flexion posture, with 30%, 40%, 50% and 60% of the maximum voluntary isometric contraction. Results: A positive correlation of the RMS (root mean square) value as a function of time was found for most of the subjects with 40% (N = 6), 50% (N = 7) and 60% (N = 8) loads of the maximum voluntary isometric contraction. Conclusions: It was concluded, from this study, that the proposed protocol provides evidence, through the electromyographic signal, of the development of fatigue in the erector spinae muscle with loads of 40%, 50% and 60% of the maximum voluntary isometric contraction. The protocol also allows the electromyographic fatigue threshold and its probable applicability in the diagnosis of this phenomenon during repetitive activities to be determined.

Air-particle abrasion on zirconia ceramic using different protocols: Effects on biaxial flexural strength after cyclic loading, phase transformation and surface topography

This study evaluated the effect of different air-particle abrasion protocols on the biaxial flexural strength and structural stability of zirconia ceramics. Zirconia ceramic specimens (ISO 6872) (Lava, 3M ESPE) were obtained (N=336). The specimens (N=118, n=20 per group) were randomly assigned to one of the air-abrasion protocols: Gr1: Control (as-sintered); Gr2: 50 μm Al2O3 (2.5 bar); Gr3: 50 μm Al2O3 (3.5 bar); Gr4: 110 μm Al2O3(2.5 bar); Gr5: 110 μm Al2O3 (3.5 bar); Gr6: 30 μm SiO2 (2.5 bar) (CoJet); Gr7: 30 μm SiO2(3.5 bar); Gr8: 110 μm SiO2 (2.5 bar) (Rocatec Plus); and Gr9: 110 μm SiO2 (3.5 bar) (duration: 20 s, distance: 10 mm). While half of the specimens were tested immediately, the other half was subjected to cyclic loading in water (100,000 cycles; 50 N, 4 Hz, 37 °°C) prior to biaxial flexural strength test (ISO 6872). Phase transformation (t→m), relative amount of transformed monoclinic zirconia (FM), transformed zone depth (TZD) and surface roughness were measured. Particle type (p=0.2746), pressure (p=0.5084) and cyclic loading (p=0.1610) did not influence the flexural strength. Except for the air-abraded group with 110 μm Al2O3 at 3.5 bar, all air-abrasion protocols increased the biaxial flexural strength (MPa) (Controlnon-aged: 1030±153, Controlaged: 1138±138; Experimentalnon-aged: 1307±184-1554±124; Experimentalaged: 1308±118-1451±135) in both non-aged and aged conditions, respectively. Surface roughness (Ra) was the highest with 110 μm Al2O3(0.84 μm. FM values ranged from 0% to 27.21%, higher value for the Rocatec Plus (110 μm SiO2) and 110 μm Al2O3 groups at 3.5 bar pressure. TZD ranged between 0 and 1.43 μm, with the highest values for Rocatec Plus and 110 μm Al2O3 groups at 3.5 bar pressure. © 2013 Elsevier Ltd.

Influence of Three Types of Abutments on Preload Values Before and After Cyclic Loading with Structural Analysis by Scanning Electron Microscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Static vertical displacement measurement of bridges using Fiber Bragg Grating (FBG) sensors

Vertical displacements are one of the most relevant parameters for structural health monitoring of bridges in both the short and long terms. Bridge managers around the globe are always looking for a simple way to measure vertical displacements of bridges. However, it is difficult to carry out such measurements. On the other hand, in recent years, with the advancement of fiber-optic technologies, fiber Bragg grating (FBG) sensors are more commonly used in structural health monitoring due to their outstanding advantages including multiplexing capability, immunity of electromagnetic interference as well as high resolution and accuracy. For these reasons, using FBG sensors is proposed to develop a simple, inexpensive and practical method to measure vertical displacements of bridges. A curvature approach for vertical displacement measurements using curvature measurements is proposed. In addition, with the successful development of FBG tilt sensors, an inclination approach is also proposed using inclination measurements. A series of simulation tests of a full- scale bridge was conducted. It shows that both of the approaches can be implemented to determine vertical displacements for bridges with various support conditions, varying stiffness (EI) along the spans and without any prior known loading. These approaches can thus measure vertical displacements for most of slab-on-girder and box-girder bridges. Besides, the approaches are feasible to implement for bridges under various loading. Moreover, with the advantages of FBG sensors, they can be implemented to monitor bridge behavior remotely and in real time. A beam loading test was conducted to determine vertical displacements using FBG strain sensors and tilt sensors. The discrepancies as compared with dial gauges reading using the curvature and inclination approaches are 0.14mm (1.1%) and 0.41mm (3.2%), respectively. Further recommendations of these approaches for developments will also be discussed at the end of the paper.

Fatigue capacity of cold-formed steel roof battens under cyclic wind uplift loads

Steel roofs made of thin cold-formed steel roof claddings and battens are widely used in low-rise residential and industrial buildings all around the world. However, they suffer from premature localised pull-through failures in the batten to rafter connections during high wind events. A recent study proposed a suitable design equation for the pull-through failures of thin steel roof battens. However, it was limited to static wind uplift loading. In contrast, most cyclone/storm events produce cyclic wind uplift forces on roofs for a significantly long period, thus causing premature fatigue pull-through failures at lower loads. Therefore, a series of constant amplitude cyclic load tests was conducted on small and full scale roof panels made of a commonly used industrial roof batten to develop their S-N curves. A series of multi-level cyclic tests, including the recently introduced low-high-low (LHL) fatigue loading test, was also undertaken to simulate a design cyclone. Using the S-N curves, the static pull-through design capacity equation was modified to include the effects of fatigue. Applicability of Miner’s rule was evaluated in order to predict the fatigue damage caused by multi-level cyclic tests such as the LHL test, and suitable modifications were made. The combined use of the modified Miner’s law and the S-N curve of roof battens will allow a conservative estimation of the fatigue design capacity of roof battens without conducting the LHL tests simulating a design cyclone. This paper presents the details of this study, and the results.

Safety Assessment of a Masonry Arch Bridge: Field Testing and Simulations

The safety of an in-service brick arch railway bridge is assessed through field testing and finite-element analysis. Different loading test train configurations have been used in the field testing. The response of the bridge in terms of displacements, strains, and accelerations is measured under the ambient and design train traffic loading conditions. Nonlinear fracture mechanics-based finite-element analyses are performed to assess the margin of safety. A parametric study is done to study the effects of tensile strength on the progress of cracking in the arch. Furthermore, a stability analysis to assess collapse of the arch caused by lateral movement at the springing of one of the abutments that is elastically supported is carried out. The margin of safety with respect to cracking and stability failure is computed. Conclusions are drawn with some remarks on the state of the bridge within the framework of the information available and inferred information. DOI: 10.1061/(ASCE)BE.1943-5592.0000338. (C) 2013 American Society of Civil Engineers.

承德公路隧道围岩分级与塌方机理分析

During tunnel constriction the classification of rock mass is widely used in tunnel design and construction. Moreover it offers the base information about tunnel investment and security. The quick classification of rock mass is very important for not delaying tunnel construction. Nowadays the tunnel engineers usually use initial survey files which are obtained by probe drilling to design a tunnel. It brings the problem that initial surrounding rock classification is usually much different from the real condition during the tunnel construction. Because initial surrounding rock lack credibility, it need us to make real time surrounding rock classification during the tunnel construction, and feed back the result to designers and constructors. Therefore, to find a quick wall rock classification method is very important not only for the time limit for a project but also for not delaying tunnel construction. Not all but many tunnels and underground constructions do suffer form collapse during the period of construction. Although accidental collapse in a large project in civil and geotechnical engineering sometimes appears to be a local event, if it occurred, it can bring about casualties, disrupted，production, construction delay, environmental damage, capital cost etc，therefore, it has been a difficult problem ,both in theory and in practice, establishing how to prevent underground structures form collapse and how to handle such an event in case in occurs. It is important to develop effective solutions and technical measures to prevent and control the collapse. According to the tunnel collapse occurred in Cheng De this paper analyze the main collapse mechanism leading to tunnel collapse and summon up the disposal method when collapse happened. It may be useful for tunnel construction in Cheng De in future. This paper is base on tunnel surrounding rock classification and tunnel support tasks during the tunnel construction in Cheng De area. It aims at solving 4 important problems in tunnel design and construction. 1) The relationship between rock rebound strength and rock single axle compression strength. First we go to the face wall and do rebound test on the tunnel face, then we chose some pieces of rock and do point loading test. Form the tests record we try to find the relationship between rock rebound strength and rock single axle compression strength. 2) The relationship between the value [BQ] and the value Q. First in order to obtain the information of rock character, rock strength, degree of weathering, the structure of rock mass, the joint condition, underground water condition and so on, we go to the tunnel face to do field investigation. And then we use two kinds of rock classification method to make surrounding rock classification. Base on the works above, finally we analyze the relationship between the value [BQ] and the value Q. 3) Sum up the mechanism leading to tunnel collapse and it disposal method in Cheng De area According to the tunnel collapse occurred in Cheng De this paper analyze the main reasons leading to the tunnel collapse and sum up the disposal method when collapse happened. 4) Obtain the properties of steel frame grid by numerical simulation. First we establish the 3D numeral model of steel frame grid by ADINA, and then find the mechanics properties by numerical simulation in ADINA. Second Based on the rock mass geological structure model, we established steel frame grid numeral model which is installed in the tunnel by FLAC3D and simulated the progress of tunnel construction. We hope that the support effect in tunnel can be evaluated from the numerical simulation.

基于工程地质力学的岩土工程加固理论、技术与实践

In the engineering reinforcement of-rock and soil mass, engineers must consider how to obtain better reinforcing effect at the cost of less reinforcing expense, which, in fact, is the aim of reinforcement design. In order to accomplish the purpose, they require not only researching the material used to reinforce and its structure, but also taking into account of several important geological factors, such as the structure and property of rock and soil mass. How to improve the reinforcing effect according to engineering geomechanical principle at the respect of the reinforcement of engineering soil and rock mass is studied and discussed in this paper. The author studies the theory, technology and practice of geotechnical reinforcement based on engineering geomechanics, taking example for the soil treatment of Zhengzhou Airport, the effect analysis of reinforcement to the slope on the left bank of Wuqiangxi Hydropower Station and the reinforcing design of the No. 102 Landslide and unique sand-slide slope on the Sichuan-Tibet Highway. The paper is comprised of two parts for the convenience of discussion. In the first part, from the first chapter to the fifth chapter, trying to perform the relevant research and application at the viewpoint of soil mass engineering geomechanics, the author mainly discusses the study of reinforcing soft ground soil through dynamical consolidation and its application. Then, in the second part, from the sixth chapter to the eleventh chapter, the study of new technologies in the rock slope reinforcement and their application are discussed. The author finds that not only better reinforcing effect can be gained in the research where the principle and method of rock mass engineering geomechanics is adopted, but also new reinforcing technologies can be put forward. Zhengzhou Airport is an important one in central plains. It lies on Yellow River alluvial deposit and the structure of stratum is complex and heterogeneous. The area of airport is very large, which can result in differential settlement easily, damage of airport and aircraft accident, whereas, there are no similar experiences to dispose the foundation, so the foundation treatment become a principal problem. During the process of treatment, the method of dynamic compaction was adopted after compared with other methods using the theory of synthetic integration. Dynamic compaction is an important method to consolidate foundation, which was successfully used in the foundation of Zhengzhou Airport. For fill foundation, controlling the thickness of fill so as to make the foundation treatment can reach the design demand and optimum thickness of the fill is a difficult problem. Considering this problem, the author proposed a calculation method to evaluate the thickness of fill. The method can consider not only the self-settlement of fill but also the settlement of the ground surface under applied load so as to ensure the settlement occurred during the using period can satisfy the design demand. It is proved that the method is correct after using it to choose reasonable energy of dynamic compaction to treat foundation. At the same time, in order to examine the effect of dynamic compaction, many monitor methods were adopted in the test such as static loading test, modulus of resilience test, deep pore pressure -test, static cone penetration test and the variation of the pore volume measurement. Through the tests, the author summarized the discipline of the accumulation and dissipation of pore pressure in Yellow River alluvial deposit under the action of dynamic compaction, gave a correct division of the property change of silt and clay under dynamic compaction, determined the bearing capacity of foundation after treatment and weighted the reinforcing effect of dynamic consolidation from the variation of the soil particle in microcosmic and the parameter of soil mass' density. It can be considered that the compactness of soil is in proportion to the energy of dynamic compaction. This conclusion provided a reference to the research of the "Problem of Soil Structure-the Central Problem of Soil Mechanics in 21 Century ". It is also important to strengthen rock mass for water conservancy and electric power engineering. Slip-resistance pile and anchoring adit full of reinforced concrete are usually adopted in engineering experience to strengthen rock mass and very important for engineering. But there also some deficiency such as the weakest section can't be highlighted, the monitor is inconvenient and the diameter of pile and adit is very large etc. The author and his supervisor professor Yangzhifa invented prestressed slip-resistance pile and prestressed anchoring adit full of reinforced concrete, utilizing the advantage that the prestressed structure has better anti-tensile characteristic (this invention is to be published). These inventions overcome the disadvantages of general slip-resistance pile and anchoring adit full of reinforced concrete and have the functions of engineering prospecting, strengthening, drainage and monitor simultaneous, so they have better strengthened effect and be more convenient for monitor and more economical than traditional methods. Drainage is an important factor in treatments of rock mass and slop. In view of the traditional drainage method that drainage pore often be clogged so as to resulted in incident, professor Yangzhifa invented the method and setting of guide penetration by fiber bundle. It would take good effect to use it in prestressed slip-resistance pile and anchoring adit full of reinforced concrete. In this paper, the author took example for anchoring adit full of reinforced concrete used to strengthen Wuqiangxi left bank to simulate the strengthened effect after consolidated by prestressed slip-resistance pile, took example for 102 landslide occurred along Sichuan-Tibet highway to simulate the application of slip-resistance pile and the new technology of drainage. At the same time the author proposed the treatment method of flowing sand in Sichuan-Tibet highway, which will benefit the study on strengthening similar engineering. There are five novelties in the paper with the author's theoretical study and engineering practice: 1. Summarizing the role of pore water pressure accumulation and dissipation of the Yellow River alluvial and diluvial soil under the action of dynamical consolidation, which has instructive significance in the engineering construction under the analogical engineering geological conditions in the future. It has not been researched by the predecessors. 2. Putting forward the concept of density D in microcosmic based on the microcosmical structure study of the soil sample. Adopting D to weight the reinforcing effect of dynamic consolidation is considered to be appropriate by the means of comparing the D values of Zhengzhou Airport's ground soil before with after dynamically consolidating reinforcement, so a more convenient balancing method can be provided for engineering practice. 3. According to the deep research into the soil mass engineering geology, engineering rock and soil science, soil mechanics, as well as considerable field experiments, improving the consolidating method in airport construction, from the conventional method, which is dynamically compactmg original ground surface firstly, then filling soil and dynamically layer-consolidating or layer-compacting at last to the upgraded method, which is performing dynamical consolidation after filling soil to place totally at the extent of the certain earth-filling depth. The result of the dynamical consolidation not only complies with the specifications, but also reduces the soil treatment investment by 10 million RMB. 4. Proposing the method for calculating the height of the filled soil by the means of estimating the potential displacement produced in the original ground surface and the filled earth soil under the possible load, selecting the appropriate dynamically-compacting power and determining the virtual height of the filled earth soil. The method is proved to be effective and scientific. 5. According to the thought of Engineering Geomechanics Metal-Synthetic Methodology (EGMS), patenting two inventions (to the stage of roclamation, with Professor Yang Zhi-fa, the cooperative tutor, and etc.) in which multi-functions, engineering geological investigation, reinforcement, drainage and strength remedy, are integrated all over in one body at the viewpoint of the breakage mechanism of the rock slope.

Multibody modelling of gabion beams for impact applications

Gabions are stone-filled wire containers which are frequently used as retaining walls. However, due to their high mass, relatively low cost and visual appeal, a row of single gabion blocks, joined at the ends, has the potential to be used as a roadside impact absorption device where traditional steel or concrete devices may not be suitable. To evaluate such application, the shear and bending deformation of gabions under vehicle impact need to be investigated. In this paper, the shear response of a single gabion block is analytically modelled and a gabion beam multibody model is developed using a discretisation method to capture the deformability of the gabion structure. The material properties of the gabion beam are adopted from experimental values available in the literature and the modelling is statically validated over a three-point bending test and a distributed loading test. The results show that the discretised multibody modelling can be effectively used to describe the static deformation behaviour of gabion blocks.

Prevalencia de los síntomas otorrinolaringológicos y factores asociados en los trabajadores de una central de llamadas en la ciudad de Bogotá Colombia

La industria de las centrales de llamadas es uno de los sectores de más rápido crecimiento en el mundo desarrollado, gracias a los avances tecnológicos han permitido su uso cada vez más generalizado desarrollando servicios integrales que son accesibles las 24 horas del día. Los operadores telefónicos o tele-operadores de esta industria se ven enfrentados a jornadas laborales en las que se exponen al uso constante de la voz, utilización permanente de auriculares de comunicación, confinamiento en estaciones de trabajo delimitadas pero no aisladas; aumentando así la prevalencia de síntomas como los otorrinolaringológicos. Este estudio tiene como objeto identificar la prevalencia de síntomas otorrinolaringológicos dados por alteraciones de la voz, compromiso auditivo y síntomas de la vía respiratoria superior durante la jornada laboral de los trabajadores de una central de llamadas de una prestigiosa empresa aseguradora de la ciudad de Bogotá Colombia, así como también identificar la asociación de factores demográficos organizacionales y biológicos con los síntomas otorrinolaringológicos y analizar el medio ambiente laboral de dicha empresa y la relación de los síntomas otorrinolaringológicos con mediciones de ruido, temperatura y humedad. La población estudiada fue de 81 tele operadores de los cuales 61 (75.3%) fueron mujeres, se evidencio que las enfermedades respiratorias altas tienen una prevalencia del 36%, también se reporto una prevalencia del 85% (69) tele operadores reportaron por lo menos un síntoma de voz y solo 12 tele operadores 15% no reportaron ningún síntoma. En cuanto a la hipoacusia solo 5 (6.2%) reportaron disminución de la agudeza auditiva

Flexural properties, microleakage, and degree of conversion of a resin polymerized with conventional light and argon laser

Objective: To evaluate the flexural strength, microleakage, and degree of conversion of a microhybrid resin polymerized with argon laser and halogen lamp. Method and Materials: For both flexural test and degree of conversion analysis, 5 bar samples of composite resin were prepared and polymerized according to ISO 4049. The halogen light-curing unit was used with 500 MW/cm(2) for 20 seconds and the argon laser with 250 mW for 10 and 20 seconds. Samples were stored in distilled water in a dark environment at 37 degrees C for 24 hours. The flexural property was quantified by a 3-point loading test. For the microleakage evaluation, 60 bovine incisors were used to prepare standardized Class 5 cavities, which were restored and polished. Specimens were stored in distilled water for 24 hours at 37 degrees C and thermocycled 500 times (6 degrees C to 60 degrees C). Specimens were then immersed in art aqueous solution of basic fuchsin for 24 hours. Longitudinal sections of each restoration were obtained and examined with a stereomicroscope for qualitative evaluation of microleakage. Fourier transform (FT)-Raman RFS 100/S spectrometer (Bruker) was used to analyze the degree of conversion. Results: ANOVA showed no statistically significant differences of flexural strength between the photoactivation types evaluated in the flexural study. Microleakage data were statistically analyzed by Mann-Whitney and Kruskal-Wallis tests. Enamel margins resulted in a statistically lower degree of leakage than dentin margins. No statistically significant difference was found among the 3 types of photocuring studied. ANOVA also showed no statistically significant difference in the degree of conversion among the studied groups. Conclusion: According to the methodology used in this research, the argon laser is a possible alternative for photocuring, providing the same quality of polymerization as the halogen lamp. None of the photocured units tested in this study completely eliminated microleakage.

Provas de carga estática com carregamento lateral em estacas escavadas hélice contínua e cravadas metálicas em areia

An experimental study has been conducted to investigate the behavior of continuous flight auger (cfa) bored piles and metalic driven H-section piles under lateral loading in cohesionless soils. The piles were tested in two different areas at the same site. Both areas consisted of a 3-m thick compacted superficial fill of pure fine sand, underlain by layers of naturally occurring pure fine-thick sand. Fills are differentiated by the relative densities which were compressed, 45% e 70%, respectively. Each area received one identical pair of cfa piles and two identical pairs of H-piles. A static lateral loading test was performed in each pair of piles. In this work, the pile load test results are reported and interpreted. The horizontal coefficient of subgrade reaction was determined from the results of the loading tests and compared with values determined by correlations based on penetration resistance index of SPT tests (NSPT). p-y formulations describing the static behavior of the piles were applied to the problem under evaluation. Back Analyses were made through theoretical and experimental p-y curves for obtaining input parameters for the analytic models, among which the coefficient of horizontal reaction. The soil pile system horizontal loading at rupture was determined by the theoretical methods and the results were compared with the experimental results, checking its validity

Association Between Insulin Resistance, Glucose Intolerance, and Hypertension in Pregnancy

There is an association between insulin resistance, glucose intolerance, and essential hypertension, but the relation between insulin resistance, glucose intolerance, and hypertension diagnosed during pregnancy is not well understood. Transient hypertension of pregnancy, the new-onset nonproteinuric hypertension of late pregnancy, is associated with a high risk of later essential hypertension and glucose intolerance; thus, these conditions may have a similar pathophysiology. To assess the association between insulin resistance, glucose intolerance, essential hypertension, and subsequent development of proteinuric and nonproteinuric hypertension in pregnancy in women without underlying essential hypertension, we performed a prospective study comparing glucose (fasting, I and 2 hours postglucose load), insulin, glycosylated hemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-C), and triglycerides levels on routine screening for gestational diabetes mellitus. Women who developed hypertension in pregnancy (n = 37) had higher glycemic levels (fasting, 1 and 2 hours postglucose load) on a 100-gram oral glucose loading test, although only the fasting values showed a statistical significance (p < 0.05), and a significantly higher frequency of abnormal glucose loading tests, two hours after glucose load (>= 140 mg/dL) (p < 0.05) than women who remained normotensive (n = 180). Glucose intolerance was common in women who developed both subtypes of hypertension, particularly preeclampsia. Women who developed hypertension had greater prepregnancy body mass index (p < 0.0001), higher frequency and intensity of acanthosis nigricans (p < 0.0001), and higher baseline systolic and diastolic blood pressures (p <= 0.0001 for both), although all subjects were normotensive at baseline by study design; they also presented lower levels of HDL-C (p < 0.05). However, after adjustment for these and other potential confounders, an abnormal glucose loading test remained a significant predictor of development of hypertension (p < 0.05) and, specifically, preeclampsia (p < 0.01). There was a trend toward higher insulin and homeostasis model assessment-insulin resistance (HOMA-IR) levels in women developing any type of hypertension. When comparing women that remained normotensive to term with those with transient hypertension and preeclampsia, the preeclamptic women were born with lower weight (p < 0.05) and shorter length (p < 0.005); at screening they were older (p < 0.005), showed higher frequency and intensity of acanthosis nigricans (p < 0.0001), had higher prepregnancy BMI (p < 0.0005), as well as higher baseline systolic and diastolic blood pressures (p <= 0.0001 for both). They also showed higher HOMA-IR levels that did not show a statistical significance. When glucose tolerance status was taken in account, an association was found between increasing indexes of hypertension (p < 0.05) and of HOMA-IR (p < 0.05) with the worsening of glucose tolerance. These results suggest that insulin resistance and relative glucose intolerance are associated with an increased risk of new-onset hypertension in pregnancy, particularly preeclampsia, and support the hypothesis that insulin resistance may play a role in the pathogenesis of this disorder.